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

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.

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.

Right now, with social networks and other tools on the Internet, all of these 500 million people have a way to say what they're thinking and have their voice be heard.

I personally don't invest in a lot of companies because I think it would be a conflict of interest and Facebook doesn't typically either.

So many businesses get worried about looking like they might make a mistake, they become afraid to take any risk. Companies are set up so that people judge each other on failure. I am not going to get fired if we have a bad year. Or a bad five years. I don’t have to worry about making things look good if they’re not. I can actually set up the company to create value.

We want Facebook to be one of the best places people can go to learn how to build stuff. If you want to build a company, nothing better than jumping in and trying to build one. But Facebook is also great for entrepreneurs/hackers. If people want to come for a few years and move on and build something great, that's something we're proud of.