 
MICHAEL D. SMITH: This
afternoon I have the pleasure
of introducing Mark Zuckerberg,
which is one of our guest speakers
this semester to come and talk a
little bit about computer science
in the real world.
As most of you probably know, as
you guys all do this much more
than I do, founder of Facebook.com,
which is a social networking
program, whatever you want to call it.
Used at over 2000 schools across the
nation, and possibly the world too.
Is it the world too, or just the nation?
>> MARK ZUCKERBERG: [INAUDIBLE].
>> MICHAEL D. SMITH: OK.
So good influence for doing
some things in computer science.
He's going to tell us some
of the background of it
and what's been important and so forth.
So please join me in welcoming.
 
>> MARK ZUCKERBERG: Yo.
All right, cool.
This is the first time I've ever
had to hold one of these things.
So I'm just going to attach
it really quickly, one second.
 
All right.
Can you hear?
Is this good?
Is this amplified at all?
>> AUDIENCE: Yeah.
MARK ZUCKERBERG: All right.
Sweet.
This is like one of the first times
I've been to a lecture at Harvard.
 
I guess what's probably going to be
most useful for you guys is if I just
take you through some of the courses
that I took at Harvard where I actually
did go to lecture sometimes.
I was joking.
And sort of, like, how
different decisions
that I had to make when I was
moving along with Facebook
got impacted by different stuff
that I was learning in the classes
that I was taking.
And if all goes according to
plan, then maybe some of you guys
will come out of this thinking
that taking CS or engineering stuff
at Harvard is actually sort of useful.
So that's the game plan.
>> I think that this is
slotted for two hours.
There's no way I'm going
to speak for two hours.
I'll probably speak for like
20 minutes, or 15 minutes,
and then I'll just let
you guys ask questions.
Because I'm sure you guys
have more interesting stuff
to ask me than I could come
up with to talk about myself.
>> So I guess I'll just
kind of get started.
 
When I was here, I
started off taking 121.
I never actually took 50.
You should have gotten
the other guy who was
doing Facebook, Dustin
Moskovitz, who was my roommate.
When we got started the site was
written in PHP, which isn't something
that you learned in
one of these classes.
But fortunately, if you
have a good background in C,
the syntax is very similar, and
you can pick it up in a day or two.
>> So I started writing the site
and launched it at Harvard
in February 2004.
So I guess almost two years ago now.
And within a couple of weeks, a
few thousand people had signed up.
And we started getting
some emails from people
at other colleges asking for us
to launch it at their schools.
>> And I was taking 161 at the time.
So I don't know if you guys know
the reputation of that course,
but it was kind of heavy.
It was a really fun course, but
it didn't leave me with much time
to do anything else with Facebook.
So my roommate Dustin, who I
guess had just finished CS50,
was like, hey, I want to help out.
I want to do the expansion and help
you figure out how to do the stuff.
So I was like, you know,
that's pretty cool dude,
but you don't really know any
PHP or anything like that.
So that weekend he went home,
bought the book Perl for Dummies,
came back and was like,
alright, I'm ready to go.
I was like dude, the site is written
in PHP, not Perl, but you know,
that's cool.
>> So he picked up PHP over
a few days because, I
promise that if you have a
good background in C, then
PHP is a very simple thing to pick up.
And he just kind of went to work.
So I mean, the first big decision
that we really had to make
was in how to kind of
expand the architecture
to go from the single school type set up
that we had when it was just at Harvard
to something that
supported multiple schools.
>> So this was a decision that had
to be made on a bunch of levels,
both in the product and how
we wanted privacy to work,
but I think that one really
important decision that's
helped us scale pretty well is how
we decided to distribute the data.
>> So I don't know how much of complexity
stuff like big O notation you guys
in this class.
So I mean, one of the most complicated
computations that we do on the site
is the computation to tell how
you're connected to people.
>> Because if you can
imagine, that's stored
as sort of a series of undirected--
it's not weighted-- so undirected,
unweighted pairs of ID numbers
of people in the database.
Then if you want to figure out
who is friends with someone,
you have to look at all their friends.
Right?
So that's maybe like 100 or 200 people.
>> But then if you want to figure
out who's a friend of a friend,
or what the closest connection
is there, then you kind of
have to look at the 100 or 200
friends of each of those friends.
So it becomes at each level there's
another factor of n multiplied n, where
n is the number of friends
that each of your friends has.
So you can see that this
kind of becomes exponentially
difficult to solve for the
shortest path between people.
So if you're just looking for a
friend of a friend, that's n squared.
If you're looking for a friend of a
friend of a friend, that's n cubed.
And that's something
that traditionally was
pretty difficult for a lot of the
predecessor sites to Facebook.
And for example Friendster
had large problems with this
because they were trying to
compute paths six degrees out,
or like seven degrees out.
>> And that's something that when
you're doing like n seventh,
that just is really very hard and
it took down their site for a while.
So one of things that we kind of had
in mind when we were figuring out
how to do this was how do you
distribute the database in such a way
that this computation
becomes manageable.
>> So what we decided was
that everyone on the site
does most of their activity at the
school that they're kind of based at.
So if you're at Harvard,
then most of the people
who you're going to be seeing
and transacting with on the site
are going to be at Harvard.
It's actually probably like 90% of
the stuff that you do on the site.
>> So we decided to split up
the databases and create
one instance of MySQL database
for each school in the network.
And in doing that, if you
notice the paths that we compute
are only within the school.
So instead of say, like now
we're at six million users,
and instead of having to do n cubed
over some portion of six million,
it's just n cubed over
10,000, which is a much more
manageable type of computation.
>> So that was sort of the first
big architectural decision
that we had to make that contributed
to us not dying a few months later.
And it was probably a
pretty important one.
>> So when we first set up the site we had
just one computer that we were running.
It wasn't in our dorm room.
We were renting it.
I kind of learned my lesson for
trying to run a site out of my dorm
room a few months earlier, and
Harvard almost tried to kick me out.
>> So I ended up renting a
server off site this time.
And I guess running originally
the database and the web server.
So Apache is what we were
using in this instance
to serve the pages
from the same machine.
And because we distributed the
databases in the way that we did,
we were able to, as time went on, just
add more machines linearly and sort of
grow the site without having any
kind of exponential expansion
on the amount of machinery that we had.
>> But after we hit about
like 30 or 50 schools,
we started realizing that we could
start getting more performance out
of MySQL or Apache.
 
Some of the way that stuff was set up
just wasn't as optimal as it could.
>> So for example, when you have
MySQL machines and Apache
running on the same server, then if
something happens to that server,
then not only does the database
for that school or the schools
on that server just
stop kind of responding
in a way that will get
you anything useful,
but you can't even load any web pages.
So you get page not founds.
And that kind of sucks.
>> But another issue is that the variance
and the use from school to schools
is also not going to be perfect.
So some schools are always
going to have heavier use.
We have schools now like Penn
State that have 50,000 users.
And then the majority of the schools
still have less than 2000 users.
Because there's a lot of small
schools and a lot of schools
that don't have complete ubiquity.
>> So in trying to deal with
this issue and make it
so that you could deal with
the fact that Penn State had
50,000 people and just a
ton of users all the time,
and then you have some schools
that don't, what we decided to do
is separate out some of the web
servers from the database servers.
And make it so that we just had
a pool of Apache web servers
that we could load balance between.
And make it so that you
can use those uniformly
while just having the database
layer be sort of consistent.
>> So I don't know if this stuff is
interesting to you guys at all.
Or if this is anything that matters
to what you guys are studying now.
So if there's more stuff
that you guys would rather
know about in terms of the architecture,
then I'll leave that open to questions
later.
So I don't spend a lot of time just
talking about random applications
that you guys might
not ever care to use.
>> Let me try to find some
interesting examples.
 
So I mean, I guess one of the
things that was pretty interesting
was when we got to a
point in terms of traffic
where we started maxing
out the performance of some
of these open source applications
that are generally pretty performant.
>> So for example, MySQL is a
really good open source database.
I don't know if any of you guys
sort of in your own time mess
around and make anything with
MySQL or have used it in any way.
But it's pretty easy to use.
It's also decently quick.
Indices work pretty well.
It's not as fully featured as something
like Oracle, but it's pretty good.
>> And we got to a point
where, I think around
when we started doing like
maybe 100 million pages a day,
that we started running into
some bottlenecks on that.
So for example, a typical query on MySQL
might take two to four milliseconds.
And that's not that much.
But when you're doing 100
billion page views a day,
and each page view might
have 30 to 50 queries,
especially if you're doing
something like a profile view that
queries all kinds of different
information, then that starts to suck.
>> So we started to develop
a caching layer that
allowed quicker access to
some of the information.
And originally we were using another
open source application Memcache,
which I don't know if any of you
guys have any experience with that.
But it was pretty quick.
It got access times
down to I guess the 0.3
to 0.5 milliseconds,
which is pretty good.
>> But it also has a bunch
of distribution issues.
It's supposed to be a distributed
hash table sort of application,
where you can just attach any number
of Memcache boxes in a cluster
and be able to hook
it up and have it go.
But we ran into a lot
of issues there where
different Memcache boxes would go down.
And there was no redundancy
on the information.
So when a Memcache box went
down and you had a cache miss,
then all of a sudden you
had a lot more traffic
going to a specific set of databases.
And that would suck.
>> So as time went on, we even outgrew
Memcache and the indices on MySQL.
We still use that stuff.
But we had to build on top
of that extra redundancy.
And I think that's something that's
probably maybe a little interesting.
But I'll let you guys ask me
more questions about that later.
>> I'm not really sure what would be
interesting to talk about right now.
Maybe you guys could help out a little?
 
Go for it.
>> AUDIENCE: I'm curious about,
thinking of [INAUDIBLE]
going into an online business like
this, how you felt the atmosphere was
with big players all bringing it
to market and other big players
who you thought might
[INAUDIBLE] to mark,
or what your experience was with that.
I'd be interested, just on a technical
side, [INAUDIBLE] just ramping
up and technically how you [INAUDIBLE].
 
>> MARK ZUCKERBERG: Yeah, so that's
not a technical question at all.
But I guess I'll just like
go into question time now.
Because I'm not really sure what's
relevant stuff for me to be discussing.
So I'll just answer this.
Then anyone else who wants to ask
me questions can just go for that.
 
>> I guess I'd never really spent a lot
of time worrying about stuff like-- I
mean, there are companies
out there like Google
that could just get into your space
and do whatever you want at any time.
And I think one of the cool things
about this time in technology
is that individuals are leveraged and
able to do way more than they've really
ever been able to do before.
>> And even four years ago
when Google was started,
now they have hundreds
of thousands of machines
and probably billions of
dollars spent on equipment.
I think the generation before
Google, you couldn't even
make a site without some
big piece of hardware.
I think eBay, for example, ran
off of two $50,000 machines.
You just can't start doing that if
you're just a kid in a dorm room.
>> So I think the fact that we could
rent machines for $100 a month
and use that to scale up to a
point where we had 300,000 users
is pretty cool.
It's a pretty unique thing that that's
going on in technology right now.
It makes it so that instead of
worrying about who is the big player
and what is Google going to do
next, you can do more of-- you
can just get a lot of stuff done.
>> And instead of having to go out and
have some of the traditional business
problems, like you have to raise
capital before you can make anything,
that's no longer an issue.
So you're leveraged to do
a lot more on your own now.
I don't know if that answers
the question that you're asking.
>> But I mean, it's one of the reasons
why I think that, at this point,
it makes a lot of sense
to be studying this stuff.
Because at no point in the past could
you leverage such a small amount
of money to get powerful
enough technology
to really touch people in
the way that you can today.
Google does about 250
million pages views a day.
They have hundreds of thousands
of machines and 5,000 employees.
>> Facebook does 400
million page views a day.
That's a lot more than Google does.
And we have hundreds of machines.
And we just passed 50 employees.
And that's just a technical
generation of three or four
years in the architectures
that were created.
>> And then you go three or four years back
before that from like eBay to Google,
and it's just completely different.
Because at least Google is running
off of a lot of distributed equipment
that they have hundreds
of thousands of machines,
but the idea there was to get a lot of
shitty machines that are really cheap.
I mean, that's a big step up.
>> Because then it's like,
OK, that's more redundant.
They're not losing information.
They don't expect stuff to always work.
It's a much more mature
attitude than eBay's, which
was the only thing that
they could do at the time.
 
>> AUDIENCE: I have a question
about the DHT stuff.
>> MARK ZUCKERBERG: The what?
AUDIENCE: The Distributed
Hash Table stuff.
MARK ZUCKERBERG: Yeah, which one?
AUDIENCE: I was just
wondering if you [INAUDIBLE]
all your extensions for Memcache,
because one thing I've noticed
is that, yeah, there aren't really
good available libraries for DHT stuff.
There's all this wonderful
research, but in terms
of implementations that actually deal
with all the redundancy issues and all
those things--
>> MARK ZUCKERBERG: Yeah,
a lot of the stuff-- we
didn't necessarily extend Memcache.
We built a bunch of stuff ourselves.
Right now, it's not open source.
We considered doing it.
And I mean, there's a lot of work that
goes into making stuff open source.
And it's on top of whether or not you
want to lose the competitive advantage.
It's kind of unfortunate.
>> Because I think that if it we were just
easier to make something like that,
then you could do it.
You could just release the code.
But then there's a lot of support
and licensing and all that stuff.
We found that it's been annoying.
>> One of the things that we actually
considered making open source
was this search server that actually
that guy sitting right there
made while he was still
out in California.
And I guess we got to a point where
MySQL was lagging a little on some
of the searches that
we were trying to do.
And we decided that it
would be a cool thing
to do to make a series
of distributed machines
that could-- he doesn't
use a hash table.
What's the structure
that you use, McCollum?
>> ANDREW MCCOLLUM: [INAUDIBLE].
MARK ZUCKERBERG: So, yeah, we
thought about making that open.
But that's when we kind of had to do
all this work to come up with a license.
And we're just like,
all right, screw that.
 
Yo.
>> AUDIENCE: What do you spend most
of your work time doing these days?
>> MARK ZUCKERBERG: Hiring people.
 
I guess when, as you grow,
the most important thing
is to have smart people.
 
If you think about how, the technical
leverage stuff that I was talking about
in answering that guy's
question, as technology becomes
more generic and less
expensive, the leverage point
becomes more in the people.
So if you think about
this from a perspective
of a person to people time spent
or user time spent, or page view
analysis, because of
technology now, people
are much more leveraged
to do more things
and be more important in the equation.
>> Because of that, it's really important
to get the most intelligent people.
And also, I mean, when you're a small
company, you can be really nimble
and get a lot of stuff done.
And there's relatively
little bureaucracy.
So if you have smart people who can take
advantage of that to build cool things,
then that's awesome.
 
>> I guess, besides that,
designing new things.
There's not much
corporate bureaucracy yet.
So I don't have to
waste much time on that.
 
Keep on going?
>> AUDIENCE: Yeah, how much have you spoken
and consulted with lawyers so far?
>> MARK ZUCKERBERG: I have a lawyer
who works for me full-time.
>> AUDIENCE: OK, it is a big
part of running a business?
Would you recommend working
on [INAUDIBLE] early on?
 
>> MARK ZUCKERBERG: We didn't.
And that, I guess, provided
some annoyance later on.
Getting stuff set up
really well is good.
Getting stuff clean is really good.
>> And, I mean, no one's ever going
to tell you a lawyer is bad.
It's all just a question of opportunity
cost and what you prioritize.
I guess that, in our case, we now have
to deal with a bunch of stuff that
wasn't set up properly in the beginning.
Most of the stuff is dealt with.
It's not even a big deal anymore.
>> But instead of talking to lawyers
early on, we were making stuff.
And I think that that was probably
the right use of our time.
I think that one cool characteristic
of a lot of the companies that end up
being really successful, not
that we are really successful,
but I guess we also
fall into this bucket,
is that they started off as
someone trying to make something
cool and not someone
trying to make a company.
 
You kind of have-- Google came out of
Larry and Sergey's PhD Dissertation
at Stanford, and Yahoo came out of
just, I guess, also some Stanford guys
just kind of screwing
around in their dorm room.
And eBay came out of some guy trying to
build a marketplace for his girlfriend
to exchange PEZ dispensers.
Amazon was a little more calculated.
 
>> So I can't imagine that any of those
people really had that much advice,
and it seems to have
worked out OK for them.
But, I mean, at the same time
I'm not going to sit here
and tell you not to get advice on stuff.
And a lot of times people
are just too careful, too.
I think it's more useful to make
things happen and then apologize later
than it is to make sure that you
dot all your I's eyes now and then
just not get stuff done.
 
Yeah.
Go for it.
>> AUDIENCE: When do you think that
Facebook will reach the point where
it could become that big company
[INAUDIBLE] new idea, [INAUDIBLE]?
Do you think it will reach
that point any time soon?
How would you keep it from [INAUDIBLE]?
>> MARK ZUCKERBERG: Well,
I mean, I think that-- I
think you're kind of
always at that point.
 
I mean, most companies are
started on like a couple of ideas,
and those are a few
things that they do well.
So, I mean, Yahoo's was like we're
going to organize all this information
in the world like by directory.
And that was what they
started off doing,
and then they kind of diversified out
as time went on and built more stuff.
And a lot of that stuff is like
the core of their business now.
I mean, it's like they
didn't originally do search.
And now directory just doesn't exist.
It sucks.
There's no utility for it.
>> I mean, Google's big thing was
just like they did PageRank.
And then, I guess, out of
PageRank, they have search.
And now they kind of extend that to
do other similar type of algorithms,
searching in other spaces.
But, I mean, you can kind of tell how
all the other stuff that they're doing
is sort of tangential.
And it's like they're trying
really hard to make PageRank
and other types of
algorithms that are very
similar to that work in their
spaces, and it's just not as elegant
or pure of an idea as
the original one was.
>> So in Facebook, for example,
when it just got started,
what I thought was the most
interesting thing was just
to be able to type in someone's name
and find out information about them.
And there was hardly any of
the stuff that was there now.
There was no groups.
There was no messages even.
There was poking.
 
>> Yeah.
I mean, so it's like you kind of get
started on some kind of core idea.
And generally, the company
will do well, because I
guess the people who are starting
off working on that core idea
kind of understand that single core
idea in some sort of unique way.
But that doesn't imply that they have
any better understanding of anything
else, than anyone else.
So that's why surrounding yourself
with a lot of smart people
is really important.
>> AUDIENCE: What was-- was
there any sort of model
that was [INAUDIBLE] photo
features [INAUDIBLE] on Facebook?
Was there any sort of [INAUDIBLE]?
 
MARK ZUCKERBERG: I mean, there's a
lot of applications on the internet
now that do that stuff.
So, I mean, Flickr's a
pretty photo application.
Although I think in three weeks we
passed them in the number of photos
that we had on our site.
 
I mean, I think that the
coolest thing about photos
is that you can tag
them and the way that
makes them link to people's profiles.
And I think that that's
something that you can really
only do if you have the context of
everyone around you on the site.
That kind of requires
the ubiquity of usage.
 
So I don't know if any of the other guys
would have done that if they have that
kind of use, but they didn't.
 
>> I don't know.
Don't any of you guys
have any CS questions?
>> AUDIENCE: I'm curious.
How do you decide as you're
moving forward with the company
to pursue a technology or
not pursue a technology?
MARK ZUCKERBERG: What's an idea?
What's in the example?
>> AUDIENCE: Well, I actually
don't know much about Facebook.
What's the next thing you
want to do with pictures
and linking people together?
How do you know about figure out
which technologies are good ones?
How do you mine to find technology?
Do you have any processes
in place today that
are directed towards
those sorts of things,
or does technology just
come into the company
because you're out
someplace and somebody
mentioned something you might
want to do in terms of Facebook?
>> MARK ZUCKERBERG: So I think that our
process for filtering what technologies
to use are trust the smart people.
So we definitely have some people at
the company who are just really smart,
and I think that most of the people at
the company are generally pretty smart.
>> But there area a few
guys in particular-- I'm
not one of them-- who I think that when
they say that something is a generally
good practice to go at it,
then it's relatively-- then
they can get support
for that pretty easily.
And I think that a lot of the engineers
sort of build a consensus around that.
 
I'm trying to think of a good example.
>> I think it's somewhat goal oriented.
So then with photos,
we knew that we wanted
to support just people
uploading unlimited photos.
So, I mean, there's no
real concept of unlimited.
It's just you have to keep on adding
stuff, keep on adding storage.
And you want to make it so that it kind
of works as seamlessly as possible.
So the first thing that
we were trying to do
is, well, let's evaluate
these companies that
just do large storage for a living.
Or it's like NetApp or
something, Network Appliance.
So we talk to them for a while.
And then we're like, all right.
Well, we don't really want to go
with this single, big box approach.
We want to go with having just
a series of distributed smaller
boxes with a lot of hard
drive and a lot of RAM.
>> And so I think that the
architecture that we first built
was one where we had a
bunch of those machines
with relatively slow but very stable
disk behind a level of-- a layer
of caching boxes with a ton of RAM
that could hold most of the thumbnails
and the most frequently accessed
images in-- I guess in RAM at any time.
And then right before we
launched, it occurred to us
that we were going to have
some issues with this.
And the issues that
we were going to have
were going to be network
issues, not hardware issues.
>> So, for example, if you take
a photo album of 30 photos
and each of your photos
is three megabytes,
then you can upload 90
megabytes to Facebook.
And that kind of sucks.
All right.
I mean, it sucks because people
tend to have not optimal connections
and because our router-- I
guess most routers are set up
to only be able to handle
a gigabit at a time,
and routers are kind of expensive.
Thy are big pieces of equipment.
I don't think that there is a
distributed version of that yet.
 
>> So we couldn't, in the time frame
that we wanted to launch it,
just get a new router and get it set up.
So what we ended up doing was building a
Java applet and an ActiveX control that
coupled the choosing of the
photos that people wanted
to upload with compression on the
client side to make it smaller,
and then that way people can just
upload their photos relatively quickly.
We also saved CPU on our
side because we don't
have to do the
decompression on our side,
although that wasn't that
huge of a bottleneck.
So that worked.
>> And then we got it to
a point where we were
having uploads at a
rate of 100 a second,
and people were using the feature way
more than we thought we were going to.
And even though we had
this caching tier setup,
it just still wasn't fast enough.
I'm sure you guys remember this.
A few weeks ago, the site
was not having a good time.
 
>> So what we ended up
doing at that point was
using edge caching, like
Akamai type of stuff
to make these photos which are static
content just be closer to people.
So that way we can sort of offload
some of the equipment and the-- sort
of having to transfer these still
somewhat large files to people.
So that's where we are now, and it
seems to be working pretty well.
>> It wasn't that we had any upfront
technical genius about it.
It was just sort of that at each point
we sort of anticipated the issues
or picked them out
pretty quickly and then
had enough competence
to evaluate, I think,
what the options were
that we had and make
what I think were decent decisions
about how to execute on them.
What's that?
>> AUDIENCE: Take that to the next
level, too, in terms of the problems
you just talked about.
MARK ZUCKERBERG: Yeah.
>> AUDIENCE: Students get one year of--
you know, one computer science working
with, like, I go sit in the
corner, type on my [INAUDIBLE].
How did the company work through--
what do the software engineers do
when you guys all have to put
curly braces in the same place?
>> MARK ZUCKERBERG: What's that?
AUDIENCE: Curly braces for the
programmers in the same place.
How is the structure of the software
engineering actually done [INAUDIBLE]?
 
>> MARK ZUCKERBERG: So the way that-- I
guess the methodology that we have is
that I wanted to be sort of-- as
much of a meritocracy as possible
where the people who can come
up with the coolest solutions
and implement them the quickest
and have like the fewest bugs get
to work on the stuff that they
think is the most interesting
and go off and have the most
influence in the company.
>> So we're also on-boarding
a lot of people,
because we're hiring relatively quickly.
And in doing so, we sort
of have-- we pair up
new people who are coming in with
some-- like the better people
who are sort of at the top
of the chain, and then we
have them sort of work with those
people when they first come in,
to learn the stuff that
they're working on that-- so
that the new guys, like
the incoming class,
can sort of learn what some of
the people that are currently
at the company are working on.
And I think in doing that, they pick
up the style and the methods that we
use for doing stuff.
>> But I think that it
changes pretty quickly.
I think one difference between
the way stuff works in a company
and the way stuff works in school is
that this is a very iterative process.
And it's nice when you get stuff right
the first time, but we don't need to.
And I think that a lot of companies
go through phases, or stages,
where they don't get stuff
right the first time.
>> Like Microsoft-- I
mean, I don't know when
the last time was that they had
a good product before Version 4.
But by the time they
get to Version 4, it's
like always good for the most part.
And I think that works
out pretty well for them.
And, I mean, Google always
releases their stuff in beta.
>> So I guess we try to have multiple
people work on the same thing,
so everyone can learn from
each other and kind of pick off
some of the mistakes that might be
made that we can reduce pretty quickly.
But like, I guess in
general, the idea is
that it doesn't have to be
perfect the first time around.
And as long as you get the
architecture as right as possible,
then a lot of the other
implementation stuff
isn't going to be as big of
a deal, and you can sort of
work that out at any time.
I know if that's sort of answering
the question that you asked me.
>> AUDIENCE: So now, when
you find something
that you want to do that you
don't know so much about,
you can ask some of these
people that are working for you,
or you can get new people.
But when you started, it was just sort
of you and your roommate as a student.
And obviously, there were domain
knowledge issues of computer science
that you had to deal with
and you didn't know about.
>> I mean, how did you go about
figuring out how to do things?
Did you decide to take certain classes?
Did you get books?
Did you go hire or get
involved with some more people?
How did you work through
those issues of learning
computer science as you
worked through this?
MARK ZUCKERBERG: The internet
is a pretty good tool.
 
I think that that's
how we did most of it.
I mean, we kind of make a point
of not hiring people for skills,
because I guess the theory is
if someone has skills in an area
and has been doing it
for 10 or 15 years,
then that's probably what they can do.
And that's good, and that
mean that they can do that.
>> But if you hire someone,
say, right out of college,
or someone younger who you're just
hiring them for raw intelligence,
then the idea is that they're going to
be able to learn stuff really quickly.
And there's a lot of information
available all over the place,
and now, withing recent years, there's
good tools for sorting through that.
And I think that the most
performant people we have
are sort of younger people, who didn't
necessarily know that much about
anything specific coming out of college.
>> I mean, a good example is--
Dustin, my roommate at Harvard
wasn't even a CS major.
He was an economics major.
And he's just a really smart
dude, and was able to pick it up.
Some of the other good
people we have are
EE majors out of Stanford or Berkeley.
And they aren't even CS all the time.
Like math people-- if
you studied math, you
can learn the stuff relatively
quickly a lot of the time.
 
Yeah?
>> AUDIENCE: I guess, since you have the
infrastructure in place, right now,
when you focus on your hiring, so
you still look for tech skill people?
Or do you look for people who might have
the business knowledge to help grow you
further and make more money?
What's actually the priority
right now in growing the company?
MARK ZUCKERBERG: I
never really hire people
just because they have business skills.
It's actually kind of funny, but
knowledge of a lot of core CS stuff
is really important in business, too.
One of the main things that you
learn when you're studying CS
is complexity and scale, and that
is a huge issue in business, too.
How do you go from having
five people to 100 people,
and what's the change
in the dynamic there?
And like, how are
certain processes-- how
is a sales force going to scale
from five people to 100 people?
>> It's like the same type
of intelligence that
can figure out both of those problems.
And it might be a different type of
person who cares to solve the problems.
>> But I think that the second part
of my answer to what you said
is that I think we're
sort of continually
in the process of building
out infrastructure,
and I don't think you ever
get out of that process.
And we're kind of focusing
not on just building something
and figuring out how
to make money off of it
and sort of maximizing the value
of our business in the short term--
but instead, sort of
always looking to maximize
what the long term value would be.
And I think that in
doing that, you kind of
need to always just be building
out your base, and not at any time
be worried about maximizing your money.
 
>> AUDIENCE: This is sort of
back to the [INAUDIBLE]
Facebook, but do you guys have
issue like the day after college,
maybe something like that, with
everybody uploading pictures
all at the same time, [INAUDIBLE]?
MARK ZUCKERBERG: Our
peaks are pretty strong.
So like at 5:00 in
the morning, no matter
how many users we have signed up,
there's always like 5,000 people,
and that's it.
And then if you get to 9:00 PM
Pacific-- so like midnight here--
which I guess is like the
peak across the country,
it's close to 400,000 people
using it simultaneously.
>> And it's actually kind of interesting,
because we monitor these graphs
and we have this huge LCD
in our office, and whenever
there's a blip in the traffic,
we're like, oh crap, what happened?
And a lot of times
it's like Laguna Beach.
>> [CHUCKLES]
>> But usually it doesn't swing
that far the other way.
>> AUDIENCE: With your archive [INAUDIBLE],
if someone deletes something
from their profile, do you keep
a cache of that, and how long?
MARK ZUCKERBERG: Right now, we don't.
But we may at some point in the future.
>> AUDIENCE: To follow up on
that, what kind of issues
do you talk about at
the company in terms
of privacy and security,
all those things?
Are you worried about it at all?
You've put your [INAUDIBLE] privacy
and security statement online.
So you just put it up and
then not worry about it?
>> MARK ZUCKERBERG: Well, I think
that what makes Facebook fun
and useful is that there's a lot of
information about a lot of people
that you can get.
But what's more important
is that the information
is available to the people who
that person wants that information
to be available to.
And the flip side of that
is that the information
is available to the people that want
to have access to that information.
>> So one of the kind of core
decisions that we made
was only to let people at the same
school see each other's profiles.
And I guess the idea behind
that was that you're at Harvard.
You probably wouldn't have that
hard of a time just letting
someone else at Harvard
see your information.
But at the same time, it's
like only people at Harvard,
who you're probably going to see on
a day-to-day basis and maybe meet,
who are ever going to
want to look you up.
It's not like some kid out at
Stanford who you will never
talk to is going to be interested in
knowing what your cell phone number is
or what you're interested in.
>> So by limiting the
scope of the information
to sort of as narrow
as makes sense, I think
that we've solved a lot of those issues.
And then, we also give
people complete control
over what parts of their
profile get showed.
So we don't force
anyone to show anything,
and we give people granular control
over some of the more sensitive stuff.
>> So like, right next to
the cell phone field,
there's another field that's like,
who do you want to show this to?
Just your friends, just
people at your school, what?
We care about it,
because if people stop--
if people feel like their
information isn't private,
then that screws us
in the long term, too.
>> AUDIENCE: Just furthering on
that, I guess even though you
put the information up yourself,
what's the recourse in case,
say, you have a photo, and
somebody puts that photo up
on some message board or
some Hot or Not type site.
How do you control what users
do with the information that's
input onto your servers?
MARK ZUCKERBERG: It's very hard to
control what people do with information
that they have access to.
Right?
I mean, the best that we can do is give
people control over their information
and who can see it.
And then once they let someone see it,
it's sort of out of anyone's control.
 
>> AUDIENCE: I'm curious a bit
about [INAUDIBLE] Wall feature.
It seemed to start out maybe more like
blackboard type of thing, and then it
completely changed around.
[INAUDIBLE] like one or the other,
or if there was something
that you were thinking of?
Or was there a design change in
the process of doing [INAUDIBLE]?
>> MARK ZUCKERBERG: So I originally threw
that together in like a half an hour.
And I guess it was pretty
complicated, because-- or it
was more complicated than I
thought it was going to be.
And I think part of the
reason why we changed
it was because it didn't work
as well as we wanted it to.
I mean, the original goal
was to sort of make it
so that you can have this wiki
type thing on people's profiles,
that when you moused over something,
it showed who added that part of it.
>> But I guess there were a
lot of cases that we missed,
or it just wasn't well designed by me.
And I don't know if you guys remember,
but you used to mouse over stuff,
and it just wasn't as good.
And like, it might tell
you the wrong person,
or it might highlight more
than it was supposed to.
>> So I kind of coupled that with thinking,
this isn't even the best feature.
It would be much more interesting if
instead of having to mouse over stuff,
people could just see the picture
and the name of the person who
posted everything, without having
to go through the whole wall.
So over the summer, we
just kind of went through
and wrote a better parser for the
walls and tried to decompose them.
And then, going forward, we made
it so that you just added a post,
and it went to the top of the wall.
 
>> AUDIENCE: [INAUDIBLE] question.
Where'd you get the idea
from, for creating Facebook?
>> MARK ZUCKERBERG: I just
wanted to make something
where people can type in
someone's name and get
some information about a person.
I thought that would be cool.
 
Oh, yeah?
>> AUDIENCE: I'm interested
in the feature that you
could SMS some [INAUDIBLE] information
if you wanted and send it back.
I didn't know about people using it.
So I'm just wondering if there
actual considerations [INAUDIBLE]?
>> MARK ZUCKERBERG: So the SMS Gateways
also have an email counterpart,
so if your phone numbers is x and
you have Cingular as your provider,
then you could email x@cingular.com
or some variant of that,
and the text message
would go to your phone.
And that's a free gateway.
So, you know when you text
message people, a lot of times
depending on what your cell phone
plan is, it will cost you money.
If you do it through email, it
actually doesn't cost any money.
So that's how we chose to do it.
We were doing a high
volume of them and we
decided that it would just be a better
thing for us to-- to actually do it
the legit way and send a text
message directly to the cell phone,
as opposed to going
through the email gateways.
So we're kind of the process
of getting that set up now.
 
>> AUDIENCE: [INAUDIBLE]
Myspace [INAUDIBLE]?
>> MARK ZUCKERBERG: I think that we're
always looking for more stuff to do.
I don't think that we're
competing with Myspace.
And I think it's kind of a
different type of application.
Yeah.
 
AUDIENCE: I'm just curious.
Is there a particular reason why on
a person's profiles and school emails
and stuff [INAUDIBLE] and not as
text can be copied and pasted?
Is that [INAUDIBLE]?
>> MARK ZUCKERBERG: So I
did that so that people
couldn't go through
and scrape the pages.
We have a lot of stuff
that we put in place
to make sure that people don't
aggregate information off of Facebook.
You obviously, you can't see
profiles of people at other schools.
But also if you try to
view a lot of profiles,
it picks up that you're just viewing
an abnormal number of profiles.
>> And we also sort of-- just
by analyzing user activity,
we've built these Bayesian filters
that I guess just let us pick out
abnormal activity, like really
quickly, and just kind of show
very limited information to those users.
But one of the things
that we wanted to do,
we want to make sure-- we want to make
it especially difficult for anyone
to try to scrape email
addresses, because that's
really annoying-- if people get spammed.
So we figured that by
making it an image,
instead of plain text, that just
added an extra level of complexity
in terms of scraping.
 
>> AUDIENCE: [INAUDIBLE] pretty
valuable resources that [INAUDIBLE].
 
Do you do anything [INAUDIBLE]?
>> MARK ZUCKERBERG: Well, we can use it
to target posters to you, for example.
I don't know if any of you
bought posters off of that.
But we sort of-- we're trying to
figure out what we can do that,
but we're obviously really
sensitive to people's privacy.
And what's that?
>> AUDIENCE: Not so much for
individual [INAUDIBLE],
but just as a whole [INAUDIBLE]?
MARK ZUCKERBERG: Yeah.
I think we're actually going
to be releasing something
in late this week or next week that
shows some aggregate statistics that we
think are interesting.
I mean, this is the stuff is kind of
cool, but it's not the type of thing
that you come back to every day.
 
No CS questions?
 
MICHAEL D. SMITH: Do you
have any questions for Mark?
He might be willing to stay
around for a couple of minutes,
in case people want to not ask
you in public, but have a--
>> MARK ZUCKERBERG:
AUDIENCE: I'm especially
disappointed that Will Chen
didn't ask me any questions.
>> MICHAEL D. SMITH: We'll
work on Will later.
That's it?
No more?
We've got a couple more.
MARK ZUCKERBERG: Cool.
AUDIENCE: Do you ever
procrastinate on Facebook,
like everyone else in the room?
>> MARK ZUCKERBERG: What's that?
>> AUDIENCE: Do you ever
procrastinate on Facebook?
>> MARK ZUCKERBERG: Of course.
>> AUDIENCE: [INAUDIBLE].
>> MARK ZUCKERBERG: I mean,
I think that there's
a value to what people do on the site.
 
>> AUDIENCE: I just know
that probably many of us
would feel that the hours [INAUDIBLE].
>> MICHAEL D. SMITH: [INAUDIBLE].
 
>> MARK ZUCKERBERG: Yeah, of course.
AUDIENCE: I don't know if you can say
this, but what kinds of features can
we expect in the future?
[INAUDIBLE]
>> MARK ZUCKERBERG: Well, I can tell you
what we're going to do next two weeks.
There's the thing that
I just mentioned before,
where we're aggregating a bunch
of stats, and just show what's hot
and what's changing.
And also surprising
statistics that we've
found, like 2% of people at Harvard
are Libertarian, for example,
or something like that.
 
I think another thing that
we're going to launch hopefully
sometime either late
this week or next week,
is something that
allows people to clarify
their relationships with other People.
>> So a lot of the problems that
we kind of deal with at Facebook
aren't always technical, but there are
sometimes like they're social problems.
And it's like-- one
thing that I think is
really interesting is-- if you have
100 or 150 friends, how well do
you know each of those people, and
who are maybe like the five people
who you actually care about, like a lot.
And that's not something
that you can really
answer right now, because
the connections are binary.
You either are connected or you're not.
So I've been trying to think for a while
about how we could design something
that would make it so that people
could express how close they were
to people, in sort of an unbiased way.
>> So you can imagine, if you made a
feature that was just like-- rate
your friendship on a scale of
1 to 10, that would not work.
Because first of all,
no one would want to do
that because you're insulting someone
if you're like, you're a three.
But it's also kind of
boring, and so no one
would want to do it because of that.
And it would just be skewed by
social pressure in the same way
that the friends are.
Some people have a different
sense of what a friend is to them,
then another person would.
So if someone has 30 friends and
another person has 150 friends,
does that person actually have
more friends in real life?
Maybe or maybe not, and
maybe the person with 30 just
has a higher threshold for making
someone on a friend on Facebook.
>> So I mean, I guess that the solution
that we came up with for this
was to make-- to judge
relationships based
on bi-directional, factual statements.
So for example, I took
CS50 with this person.
Or I lived in a house with this person.
And there's just kind of a bunch of
different ways to do stuff like that.
But I figured that that would
probably be a little more accurate,
because no one is going
to-- there's no pressure
to lie about something like that.
It's not like, what
are you talking about?
I didn't take CS50 with you.
But if someone aggregates a
lot of different connections,
then that kind of means something.
So when you take someone like
Dustin, who's my roommate here,
and it's like OK, well we lived
together at Kirkland House.
Then we worked on Facebook.
Then we moved out to Palo Alto, and now
we're still working on Facebook-- then
maybe that's enough connections to
say OK, well this person clearly
has a lot to do this person.
Whereas if the only category
that you know someone through is,
this person's my Facebook friend,
then that also means something.
So I don't know.
We'll see how it works.
Nothing is for sure.
What's up?
>> AUDIENCE: Do you actually [INAUDIBLE]
people typing in information
[INAUDIBLE]?
 
>> MARK ZUCKERBERG: It's a combination.
So I think that another thing
that's pretty important for each
of these events is the
date at which they occur.
So if you had, for example, a
date on each person's friendship
with each person then that would give
you a more accurate representation
of what that meant,
because right now you
don't know what friend means to
each of the people on the network.
And because you don't know when
that friendship was formed,
you don't know what has
changed in that relationship
since that friendship was formed.
>> I mean if the person-- if friendship
means very little to someone
if you know that that happened
yesterday, that they became friends,
you still know that there's
some-- that there's some strength.
It's like a certainty thing.
There's a lower certainty
that their relationship
has diverged since that point if the
date at which the action occurred
was sooner.
 
Sorry, more recent.
So I think that's one of the
things that we're focusing on here.
So I took a course-- I
took CS50 with someone
this term is a lot different
than saying I'm a senior now
and I took CS50 with this
person when I was a freshman.
>> A lot of these-- the analysis
of how people look at this
and see the relationships
isn't necessarily--
Facebook isn't going to
rate the relationship.
It's sort of-- people have
an implicit understanding
of what the difference is between
having taken CS50 with someone this term
and having taken CS50
within three years ago.
And I think that will kind of help out.
 
What's up?
>> AUDIENCE: When you
get a new idea and you
think it's pretty cool, how
[INAUDIBLE] with how you go about it?
 
>> MARK ZUCKERBERG: Not too.
Because I think that a
lot of the stuff, we sort
have a very unique
platform for building it.
I don't think there's any other
company or group of people
in the world who could
develop this right now.
 
I mean even Google, with
their like 5,000 engineers
is not in the place to make
an application that sort
of characterizes people's
relationships like this.
>> And it's like the same thing
with the photo tagging.
We can do that because photo tagging
only works if everyone around you
is on the site.
Because otherwise you're
going to get a type of use
for it where you go
and you upload a photo
and you go to tag a bunch of people,
and they're not there, and that sucks.
So even if 50% of the people at Harvard
were on Facebook, then the tagging
and the way that we set
up would still suck.
So it only works because 97% of the
people at Harvard are on Facebook,
or whatever.
So because of that, it's like
not that big of a concern.
 
Yeah?
>> AUDIENCE: So from sort of
a software engineering,
sort of dynamic [INAUDIBLE]
way, when somebody
has one of these ideas-- like let's
aggregate this [? wider ?] statistic
and tell people, or I have a way to
measure this, that, and the other
about these people and mark up
this thing on people's profiles--
how do they go about getting
the go-ahead from everyone
else in the company to spend some of
their time technically working on that?
Or get other people to work on it
with them, and stuff like that?
>> MARK ZUCKERBERG: Mhm.
I think that a lot of people-- I mean,
the people who work at Facebook really
like working at Facebook,
I think, for the most part,
and spend a lot of
their time doing that.
And like, a lot of the
time that they're spending,
they spend working on
stuff that might be
sort of strategically important to
what we're trying to do at that point.
But also, a lot of people just
mess around with the code base,
and kind of put if-statements in
there that's like, if the user is me,
then put this in there.
>> And so I walk around to different
people's places during the day,
or people come and talk to me.
Like, I hold CEO office hours as a
joke, like from 2:00 to 4:00 every day--
not today.
And people just come and show me
different stuff that they're doing,
and a lot of it is
relatively cool, and stuff
that I wouldn't have
necessarily thought of.
>> So I mean, you asked
before if we were saving,
if we were archiving, old profile
information, and one of the reasons
why I said that we
might start doing it is
because one of the guys at the company
came up with something where it's like,
so you go to your friend's page, and
it shows your recently updated friends.
And then you click on that,
and it shows their new profile.
But there's no indication
of what changed.
>> So one of the guys made something that
keeps an old version of his profile,
and then makes it so that when you
go to his profile when he updates it,
it highlights in yellow the
parts of it that were changed.
And I think that that's pretty cool.
And it's not a huge project--
I mean, it actually kind of is,
if we have to start storing
everyone's information.
>> But I mean, it's somewhat cool.
It's not the type of thing that you
necessarily are bound to come up,
but I definitely think it's a pretty
big improvement over what we have now.
Now, it's really hard to go to
someone's profile and tell what changed.
And that's just the most
recent example that I have.
>> AUDIENCE: Do you have time to allow
people to change the look of each page?
[INAUDIBLE]?
 
>> MARK ZUCKERBERG: So, I
don't want to do that.
And the reason is because I think
that Facebook is a directory,
and the primary purpose
is to look up someone.
Right?
Like type in their name and get
some information about them.
And one of the things
that's really useful
is that everyone's page is
structured in the same way.
>> So if you want to see
if someone's single,
you don't have to scan down the columns
until you get to relationship status.
You just know where that is.
So you click, go-- your
eyes just go to that thing.
But if you had different people
changing their CSSes in different ways,
then that could become
annoying-- especially
if people are doing stuff like dark
blue text on black backgrounds.
It just gets kind of obnoxious.
>> AUDIENCE: How successful has
the Facebook [INAUDIBLE] been,
and what do you see as differences
in the purpose [INAUDIBLE]?
 
>> MARK ZUCKERBERG: The purpose-- for
me, the high school one was the same.
I think that the application--
this is going to probably
sound pretty stupid-- but wanting
to look people up, I think,
is kind of a core human desire.
Right?
I think that people just want to
know stuff about other people.
So I think that providing an
interface where people can just
type in someone's name and get
some information about them
is generally a pretty useful thing.
So growth has been pretty good.
>> It was tough to figure out
exactly how to gauge it,
because when we did college,
we opened it up at Harvard.
Then we opened it up at a
couple colleges around Harvard.
And the idea was always, we were
really short on money and equipment.
So while getting as little
equipment as possible,
we want to maximize our growth.
So we want to launch
at the schools that we
think are going to grow the
quickest, based on the fact
that the people at those schools
are going to have the most
number of friends at the
schools that we're already at.
We took a different
approach for high school,
because we could just launch
it everywhere at the same time.
So we didn't really know
how it was going to grow.
I think it's growing at more than 5,000
people a day, which is pretty good.
 
Yeah?
>> AUDIENCE: When you
started Facebook, did you
intend for it to become
this full-fledged business?
MARK ZUCKERBERG: No.
AUDIENCE: Well, how did you [INAUDIBLE]?
 
>> MARK ZUCKERBERG: I remember
thinking that it would be cool
if you could have a
directory of everyone.
I remember arguing with my parents
about this, because after I almost
got kicked out of school for this
project that I did before Facebook,
they were like, what good could
possibly come of doing something new?
And I'm like, no, this is pretty cool.
Just imagine how cool it would be if
you could just type in someone's name
and get some information about them.
And they were just like, I don't see it.
And I'm like, well, we'll
just do it at Harvard for now,
but imagine what happens if one day,
you can just type in anyone's name
and get some information about them.
And like, that would
be kind of cool, right?
 
So they didn't buy it, but now they do.
>> [LAUGHTER]
>> Yeah, so I don't know.
I guess at each phase, we're just
kind of looking at a natural way
to preserve the
integrity of the network,
and also to make it so
that it's more useful-- I
guess is the answer to that question.
Yeah?
>> AUDIENCE: Are there certain
skills, particularly [INAUDIBLE],
that you [INAUDIBLE] or you would
suggest for someone to study?
 
MARK ZUCKERBERG: I just suggest that you
take the hardest courses that you can,
because you learn the most when
you challenge yourself, right?
So like 161 just ruined my life,
and I learned so much from it.
121 I also found pretty hard.
124 kind of changed the
way I thought about stuff.
 
>> What 124 taught me that
I think was really useful
was that there are-- I
think a lot of people focus
on how to do stuff as
well as possible, and how
to make the most efficient algorithm.
But what has always gotten us by isn't
doing stuff in the most efficient way,
but laying the framework
in a pretty efficient way.
So I mean, it kind of teaches
you both sides of the problem,
like data structures and algorithms,
and how the setup is really important.
And that's definitely saved our
ass in scaling a lot of times.
 
>> I don't know.
Work with smart people.
Learn from people.
 
AUDIENCE: One of the things that
I've noticed about Facebook, compared
to other social networking space, is
that it's actually a lot easier to use.
Do you have people-- like your employees
just putting whatever pieces they think
are cool.
Do you have separate stability people
to ensure it all works all together?
>> MARK ZUCKERBERG: People can
make whatever they want,
but that doesn't mean they
can put it on the site.
So I think that before stuff goes
on the site, a lot of people see it.
I mean, I definitely check off
on it before it can go live.
But I mean, I think that people have
a lot of creativity to do cool stuff.
And a lot of times, it's like
someone can come up with a cool idea,
but that doesn't mean it's the
final way that it would happen.
>> So for example, people highlighting
in yellow what the changes are
in their profile-- I think that
just the concept of highlighting
stuff that has changed is
really good, but the interface
that that guy used for it isn't
what I think is the best one.
And the way that he's storing
the old profile information
isn't optimal either.
And that kind of is cool, because
he was just doing it for himself.
But if we were ever going to make
something live out of that, which
I want to, we do in a different way.
And it's more just like a mock-up.
>> AUDIENCE: So like, the ideas
come from the ground, up,
and then [? it's just ?]
[? tossed ?] [? down the line? ?]
>> MARK ZUCKERBERG: I
mean, it goes both ways.
And I'm not completely unopinionated.
 
MICHAEL D. SMITH: [INAUDIBLE].
 
>> AUDIENCE: I actually have a
question about the [INAUDIBLE].
So, going back about the
[INAUDIBLE] and [INAUDIBLE] privacy.
And it's a different platform?
>> MARK ZUCKERBERG: Yeah.
>> AUDIENCE: So college people
are over 18 and allowed
to post whatever pictures they
want, and they're not really
incriminating themselves, except
possibly for drugs and alcohol?
I've seen pictures on
Facebook where my younger
cousins are drinking
and stuff like that.
But when you go to the high school
kids, they're 15 and 16 and younger.
>> And are you guys just
saying, it's the internet,
and if they want to incriminate
themselves and things like that,
is that OK?
Or do you guys filter the pictures
that high school students put up
and the information they write?
Or do you just [INAUDIBLE]?
MARK ZUCKERBERG: So a lot of the
solutions that we come up with stuff
aren't technical or organizational,
but just applying social pressure
in good ways.
So Myspace has-- almost
a third of their staff
is monitoring the pictures that
get uploaded for pornography.
We hardly ever have any
pornography uploaded,
and I think that a lot of
the reason is that people
use their real names on Facebook, and
your real email address for school.
And if you have that, then you're
not going to upload pornography.
And I think that that's a
really simple social solution
to a possibly complex technical issue.
>> So that said, we changed some of
the features around for high school.
For example, we took
parties out, because we
figured that parents
would get pissed off
or they would just break up all
the keg parties really quickly,
and that would suck for everyone.
>> [CHUCKLES]
>> I don't know.
We deemphasize contact
information in high school.
Yeah.
AUDIENCE: All right, we end here.
If you have other questions, feel
free to come down and talk to Mark.
Thank you very much.
>> MARK ZUCKERBERG: Yeah.
[APPLAUSE]
