The unsupervised learning is the way most people will learn in the future. You have this model of how the world works in your head and you're refining it to predict what you think is going to happen in the future.

Google, I think, in some ways, is more competitive and certainly is trying to build their own little version of Facebook.

When you give people ability to stay connected with all the people they care about, and you make it so they can express new things about themselves or in communication with other people who they care about, then you just open up new possibilities. You make it so people can stay connected in ways that they couldn't before.

I think that people just have this core desire to express who they are. And I think that's always existed.

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

The world is changing so quickly, with mobile stuff and different platforms emerging, that I think it's more likely that the biggest competitor for Facebook is someone that we haven't heard of. What that means for us is that we should just really stay focused on what we're doing.

The biggest risk is not taking any risk... In a world that changing really quickly, the only strategy that is guaranteed to fail is not taking risks.