My friends are people who like building cool stuff. We always have this joke about people who want to just start companies without making something valuable. There's a lot of that in Silicon Valley.

If I were starting now I would do things very differently. I didn't know anything. In Silicon Valley, you get this feeling that you have to be out here. But it's not the only place to be. If I were starting now, I would have stayed in Boston. [Silicon Valley] is a little short-term focused and that bothers me.

The world is changing so quickly, with mobile stuff and different platforms emerging, that I think it's more likely that the biggest competitor for Facebook is someone that we haven't heard of. What that means for us is that we should just really stay focused on what we're doing.

This is a perverse thing, personally, but I would rather be in the cycle where people are underestimating us. It gives us latitude to go out and make big bets that excite and amaze people.

For the first time we're allowing developers who don't work at Facebook to develop applications just as if they were. That's a big deal because it means that all developers have a new way of doing business if they choose to take advantage of it. There are whole companies that are forming whose only product is a Facebook Platform application.

Connectivity just can't be a privilege for people in the richest countries. We believe that connecting everyone in the world is one of the great challenges of our generation, and that's why we are happy to play whatever small part in that that we can.

The thing that we are trying to do at Facebook is just help people connect and communicate more efficiently.