We just think that there are all these different ways that people want to share, and that compressing them all into a single blue app is not the right format of the future.

It used to be the case, like you'd switch jobs, and then maybe you wouldn't keep in touch with all the people that you knew from that old job, just because it was too hard. But one of the things that Facebook does is it makes it really easy to just stay in touch with all these people.

People love photos. Photos originally weren't that big a part of the idea for Facebook, but we just found that people really like them, so we built out this functionality.

When we are thinking about stuff like embeds, we are not thinking about how we are competing with YouTube. We are thinking about how are we going to make it more useful for people to share stuff on Facebook.

Just take terrorism, for example. We have a team of more than 200 people working on counterterrorism. I mean, that's pretty intense. That's not like what people think about what Facebook is.

I mean, we've built a lot of products that we think are good, and will help people share photos and share videos and write messages to each other. But it's really all about how people are spreading Facebook around the world in all these different countries. And that's what's so amazing about the scale that it's at today.