We're a community of a billion-plus people, and the best-selling phones - apart from the iPhone - can sell 10, 20 million. If we did build a phone, we'd only reach 1 or 2 percent of our users. That doesn't do anything awesome for us. We wanted to turn as many phones as possible into 'Facebook phones.' That's what Facebook Home is.

One of the big themes for the next chapter of what we do is I want to be able to build what I think are the ideal experiences, not just what you're allowed to build on some platform that someone else built, but what is actually, if you can think from first principles, what is the ideal social experience.

We are at a crossroads in the music business: with the rise of the internet, the world we live in has changed, and the past is not coming back. But I see the glass as half-full: the internet and social networking are new avenues for the next Bob Dylan to be born on.

If you had gone to a customer in 2013 and said "Would you like a black, always-on cylinder in your kitchen about the size of a Pringles can that you can talk to and ask questions, that also turns on your lights and plays music?" I guarantee you they'd have looked at you strangely and said, "No, thank you."

So I think that the scale of the systems has created this responsibility for us, where we have to be more proactive about finding and addressing issues [harmful content]. And we can do that both by building technology that is possible now, but wasn't even possible five or ten years ago, and by hiring people at a scale that would not have been possible for us before.

Facebook is shaping a broader web. If you look back for the past five or seven years, the story about social networking has really been about getting people connected. But if you look forward for the next five years, I think that the story people are going to remember five years from now isn't how this one site was built; it is how every single service that you use is now going to be better with your friends.