Our strategy is very horizontal. We're trying to build a social layer for everything. Basically we're trying to make it so that every app everywhere can be social whether it's on the web, or mobile, or other devices.

I mostly built stuff that I liked.

Our mission is to make the world more open and connected. We do this by giving people the power to share whatever they want and be connected to whoever they want, no matter where they are.

Facebook is inherently viral. There are lots of sites that include a contact importer, and for lots of them it doesn't really make sense. For Facebook it fits so well. It wasn't until a few years in that we started building some tools that made it easier to import friends to the site. That was a huge thing that spiked growth.

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.

The last six years have been a lot of coding and focus and hard work. But maybe it would be fun to remember it as partying and all this crazy drama.

The days of you having a different image for your work friends or co-workers and for the other people you know are probably coming to an end pretty quickly. Having two identities for yourself is an example of a lack of integrity.