I think there's confusion around what the point of social networks is. A lot of different companies characterized as social networks have different goals - some serve the function of business networking, some are media portals. What we're trying to do is just make it really efficient for people to communicate, get information and share information.

Every application will be designed from the ground up to use real identity and friends.

Think about what people are doing on Facebook today. They're keeping up with their friends and family, but they're also building an image and identity for themselves, which in a sense is their brand. They're connecting with the audience that they want to connect to. It's almost a disadvantage if you're not on it now.

Just because you can build a machine that is better than a person at something doesn't mean that it is going to have the ability to learn new domains or connect different types of information or context to do superhuman things. This is critically important to appreciate.

I think video is a mega trend, almost as big as mobile.

Our work to improve privacy continues today.

It's tough to say, exactly, what things will look like in three to five years, but there's a lot of work to do in just moving along the path that we've already set out.