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.

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.

There have been misperceptions that we're trying to make all the information open on Facebook, and that's completely false. There are big buckets of information that we recommend that you share with only your friends privately. Then some of the more basic information, we recommend that that's visible to everyone.

When I'm introspective about the last few years I think the biggest mistake that we made, as a company, is betting too much on HTML5 as opposed to native... because it just wasn't there. And it's not that HTML5 is bad. I'm actually, on long-term, really excited about it. One of the things that's interesting is we actually have more people on a daily basis using mobile Web Facebook than we have using our iOS or Android apps combined. So mobile Web is a big thing for us.

Facebook is inherently viral. There are lots of sites that include a contact importer, and for lots of them it doesn't really make sense. For Facebook it fits so well. It wasn't until a few years in that we started building some tools that made it easier to import friends to the site. That was a huge thing that spiked growth.

We started off as this platform inside Facebook; and we were pretty clear from the beginning that that wasn't where it was going to end up. A lot of people saw it and asked, 'Why is Facebook trying to get all these applications inside Facebook when the web is clearly the platform?' And we actually agreed with that.