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.

In my experience everyone will have a different view of the right level of tax so governments need to provide clear guidance that conforms to a set of international standards that all governments accept.

What really motivates people at Facebook is building stuff that they're proud of.

This is our commitment to users and the people who use our service, is that Facebook's a free service. It's free now. It will always be free. We make money through having advertisements and things like that.

The companies that work are the ones that people really care about and have a vision for the world so do something you like.

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.

In addition to building better products, a more open world will also encourage businesses to engage with their customers directly and authentically. More than four million businesses have Pages on Facebook that they use to have a dialogue with their customers. We expect this trend to grow as well.