Advertising works most effectively when it's in line with what people are already trying to do. And people are trying to communicate in a certain way on Facebook - they share information with their friends, they learn about what their friends are doing - so there's really a whole new opportunity for a new type of advertising model within that.

I made so many mistakes in running the company so far, basically any mistake you can think of I probably made. I think, if anything, the Facebook story is a great example of how if you're building a product that people love you can make a lot of mistakes

The web is at a really important turning point right now. Up until recently, the default on the web has been that most things aren’t social and most things don’t use your real identity. We’re building toward a web where the default is social.

With some of the issues around the Snowden leaks and what the NSA was doing I think have scared people around the world and I think in many ways rightfully so.

People influence people. Nothing influences people more than a recommendation from a trusted friend. A trusted referral influences people more than the best broadcast message. A trusted referral is the Holy Grail of advertising.

If you just work on stuff that you like and you're passionate about, you don't have to have a master plan with how things will play out.

AI systems will enable doctors to diagnose diseases and treat people better, so blocking that progress is probably one of the worst things you can do for making the world better.