This is our commitment to users and the people who use our service, is that Facebook's a free service. It's free now. It will always be free. We make money through having advertisements and things like that.

It only took me two weeks to build the first version of Facebook because I had so much stuff before then.

Of course the Silicon Valley is unique and Berlin is not yet comparable. But of all the different cities that are building a startup infrastructure, Berlin is the one with the most similar energy.

Find that thing you are super passionate about. A lot of founding principles of Facebook are that if people have access to more information and are more connected, it will make the world better; people will have more understanding, more empathy. That’s the guiding principle for me. On hard days, I really just step back, and that’s the thing that keeps me going.

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

It's tough to say, exactly, what things will look like in three to five years, but there's a lot of work to do in just moving along the path that we've already set out.

Connectivity just can't be a privilege for people in the richest countries. We believe that connecting everyone in the world is one of the great challenges of our generation, and that's why we are happy to play whatever small part in that that we can.