We we want to help people find the videos. They're interested in watching and
we start with the premise that
there are hundreds of hours of video that each viewer would like to watch and
We're trying to figure out a way to connect those viewers with that 100 hours of video
My name is Christos Kudrow
And I'm responsible for search and discovery on YouTube the easiest thing which actually is not always that easy is
If someone were to search for a video, right?
So if you search for a video you're looking for something particular
We want to make sure that that shows up right at the top of the search results?
But even that can sometimes be hard because searches are ambiguous and even when the search itself isn't ambiguous
It's not always clear which video you are looking for
Because there's a lot of videos about just about every possible imaginable thing on YouTube, but then there's another problem
which is the fact that you may not know all the things that there are for you to watch on YouTube and so
What if it doesn't occur to you to search for something I used to pole-vault?
I wouldn't imagine that they are pole-vaulting videos on YouTube
But how am I ever gonna find them if I don't bother to search for them well somehow?
We've got to connect you with those videos as well. Why do you feel compelled to connect me with a video?
I wasn't looking for is that a business thing for you because you want to keep people engaged with your product
we know that creators uploaded these videos and
There are viewers interested in these videos
And we feel like it's our job to make that connection if we're not gonna help make that connection
Why should the creator's bother to upload those videos?
I mean that's one thing that I'd like to make clear is that our success depends on helping the creators find their viewers?
The simplest thing is that if we see you watch one of a certain kind of video then?
We know that other people who watch that video in the past?
Went on to watch this other video
And so it's quite natural that if we see you've watched this first one that we might think that you watch that
You'd want to watch that other one, too. That's mostly a matter of just accounting more than anything else
It's just keeping track of which videos get watched together and so so that's the simplest way
We do it if you take that to a more sophisticated level let's you watched a few videos about Lionel Messi
And you watched a few others about Cristiano Ronaldo. I think maybe you might be interested in soccer
So we might recommend to a video that isn't just about lionel Messi or Cristiano Ronaldo, but some other soccer team
That's playing because you've demonstrated some evidence in a in the broader subject another way that we might find to recommend things to you are
videos that are popular in your
Geographical area so
as you can imagine
Bollywood is very popular in India
It's also popular among
People outside of India but in order to recommend it to those people we would want to see some evidence that they are
Interested in Bollywood some of this is quite obvious, but also some of it's quite crude. You know geographic areas
You're an engineer. You like bollywood how sophisticated are you guys getting with this now. I think the sophistication comes from
figuring out what's important about the video that indicates your interest in it, so
For instance you might have watched some soccer videos, but it was because those were the most amazing goals
And you're not really that interested in soccer, but you're really interested in
Just amazing sporting things
or you might have watched those videos because
they were from a team that you happen to follow because that's an area of the world that you're from and so the
sophistication comes in separate separating those two kinds of associations
Or even in a more crude level in figuring out. What's important about that video that?
That would make us want to suggest it to some other person
Do you have to understand people or are you just like just number crunchers?
The human understanding part is where we take our intuition for what Sorts of changes. We might try next
you could imagine that there's a lot of things that we could try and
We can't do all of them at once and so we have to use some
Intuition about which sort of things we expect might be more or less successful than than other things first of all we look at
experiments a lot
So we're running a b tests on YouTube itself we also
do
qualitative research, so we
invite people to come and
sit with us and
Watch them use YouTube and ask them the kinds of things they're interested in and ask them that they would expect to find that on
YouTube if they've ever seen that on YouTube
you know how would they go about finding it on YouTube and
and we use those sorts of qualitative analyses to try to guide our intuition for what sort of experiments we run but
it all comes back to
making these broad changes and then experimenting with them and
What's important about that is because each change that we make because we've done experiments. We can be sure that it's improved the situation
Now it may not have improved it
Uniformly across the board but overall it's it's been an improvement. What is the biggest grunt and who does it come from?
The biggest gripe is you have a billion videos and I can't find anything good to watch
and
That's that's basically solving that problem for the viewers is our mission
of course people people often say as well that they can't find the video that they're looking for and
you know there's just many many different queries and ways that people go about looking for things and
You know we we keep working on them one after another until we figure them out
Well, it's easy for our systems to get confused
By in my case
I'll give you an example a friend sends me a video about a
Ski race from in Southern California, and it's because my cousin has a boat entered in this ski race
I watch his video and it's actually quite long and then I watch a couple more videos
But I'm not really very interested in this sort of thing
The next day I come back, and there's more videos waiting for me about this ski race. I think okay
Well that's fine, but two weeks later. I come back, and there's yet more videos about this case, and I think to myself
I'm sorry that I watched those videos about the skI race
you got me I did but but
What do I have to do to get you to realize that I'm not Gonna watch any more of these?
Well, I mean it's easy for our systems to become confused about the fact that you happen to have watched it at one time
But you're not really interested in it very much
As opposed to well you you watched a little bit less of something
But that's something that you really like to see more of and so
We we don't have
The information we have to go on is what you and other people have watched in the past and so using all of that
And by the way, it's only you and a billion other people
using all of that and trying to make sense of it is is what becomes hard do you build a
Random chance Element into it. I'm not saying like here's a completely random video
But does it allow for a degree of this is another baseball video, but it's bit of a wild card
Or is then is that not because I guess I'm touching on making it a modulus
we do work on trying to increase diversity and the challenge there is that
We have an intuitive belief that increasing Diversity will lead to
The opportunity to get even even more viewership in the future, but every time we try to increase diversity
We tend to reduce the amount of Viewership we have in the short term
Well, I think it's because we haven't quite gotten it right yet, and so um you know until we can until we can
recommend, sort of
Unexpected things that are almost always, right?
People will just go away
They won't see as much of what they were looking for or what they expected and they go away
And so I guess it's a quite a high bar to add some diverse things there
And so even though we have this intuition and our experiments tend to make us more conservative with it
That's the way that we want to go about trying to add
I would call it that I would say that are
The naive approach to trying to increase diversity would be to add a random element
and I can assure you that that's not going to work because
You give up too much viewership in the short term and so what we've learned. Is that random isn't good enough and
We need to make it so that we're almost always right when we add some diverse and unexpected element
my holy Grail is
To come to YouTube and have it
find the hundreds of hours of videos that I can't stop watching because
those are the ones that I'm interested in and
I think the important point about this is that
it's not going to be the same as
Yours or someone else's
and you might think
Well how different can it be I mean you know I and all my friends seem to like all the same videos that we see
On YouTube and while that may be true
think about
you know think about some children that you know and
They're you know their favorite videos probably won't will be different than yours and then think about your parents
their videos would probably be different than yours and now think about the people in another country and
How different what they're interested in watching is from yours like we need to solve this problem for everybody
across the across the world and
That is really the holy grail is how do we connect?
each one of those people with their
Diverse interests with the videos they're looking for and want to watch I think the most important thing is that
We are very interested in helping the Creator's
connect to their fans and
Helping them increase their viewership because that's entirely in our interests
And so that's the thing that I want to make sure people understand is that when we make changes to things
It's because we absolutely believe that it improves the ability for creators to be successful
and
everybody was going to click on that one and
When someone's writing code the video guy they need to put the logic in the code that says you know where you should stop
