Open Graph is a language for structuring content and sharing that goes on in other apps, and we're continuing to build it out longer term. But we found we need to build more specific experiences around categories like music or movies. Where we've taken the time to build those specific experiences, stuff has gone quite well.

Millions of people around the world love the Instagram app and the brand associated with it, and our goal is to help spread this app and brand to even more people.

People will always want more immersive ways to express themselves. So if you go back ten years ago on the internet, most of what people shared and consumed was text. Now a lot of it is photos. I think, going forward, a lot of it is going to be videos, getting richer and richer.

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.

Helping a billion people connect is amazing, humbling and by far the thing I am most proud of in my life.

Advertising works most effectively when it's in line with what people are already trying to do. And people are trying to communicate in a certain way on Facebook - they share information with their friends, they learn about what their friends are doing - so there's really a whole new opportunity for a new type of advertising model within that.