By giving people the power to share, we're making the world more transparent.

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.

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.

The ability to share whole scenes form our lives will be a valuable thing over time.

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.

I generally think if you do good things for people in the world, that comes back and you benefit from it over time.

The thing I really care about is the mission, making the world open.