Mobile is a lot closer to TV than it is to desktop.

On engagement, we're already seeing that mobile users are more likely to be daily active users than desktop users. They're more likely to use Facebook six or seven days of the week.

Our role is to be a platform for making all of these apps more social, and it's kind of an extension of what we see happening on the web, with the exception of mobile, which I think will be even more important than the web in a few years - maybe even sooner.

One of my big regrets is that Facebook hasn't had a major chance to shape the mobile operating system ecosystem.

Video is growing very quickly on Facebook. A lot of people compare that to YouTube. I think that kind of makes sense. YouTube isn't the only video service, but I think it's the biggest, and it probably makes more sense to compare Facebook video to YouTube rather than Netflix because that's a completely different kind of content.

When people are connected, we can just do some great things. They have the opportunity to get access to jobs, education, health, communications. We have the opportunity to bring the people we care about closer to us. It really makes a big difference.