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.

When you give everyone a voice and give people power, the system usually ends up in a really good place. So, what we view our role as, is giving people that power.

Companies face a handful of different risks, whether it is competitors or different market environments. But I think that people focus way too much on competitors and not enough on their own execution.

When I started Facebook from my dorm room in 2004, the idea that my roommates and I talked about all the time was a world that was more open.

I think there's confusion around what the point of social networks is. A lot of different companies characterized as social networks have different goals - some serve the function of business networking, some are media portals. What we're trying to do is just make it really efficient for people to communicate, get information and share information.

Virtual Reality is going to be an important technology. I am pretty confident about this.

The most important thing is to keep your team as small as possible.