Facebook was not originally created to be a company. It was built to accomplish a social mission - to make the world more open and connected.

Building a mission and building a business go hand-in-hand. It is true that the primary thing that makes me excited about what we're doing is the mission, but I also think, from the very beginning, we've had this healthy understanding which is that we need to do both.

Almost any mistake you can make in running a company, I've probably made

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.

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.

My number one piece of advice is: you should learn how to program.

In a lot of ways Berlin is a symbol for me of Facebook's mission: bringing people together, connecting people and breaking down boundaries.