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.

Advertising works most effectively when it's in line with what people are already trying to do.

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.

A lot of the time the experts, the people who are supposed to be able to tell you what to do, will tell you that you can't do something even when you know you can. And a lot of the time it's your friends ... who tell you you can do it.

What really motivates people at Facebook is building stuff that they're proud of.

There is a huge need and a huge opportunity to get everyone in the world connected, to give everyone a voice and to help transform society for the future. The scale of the technology and infrastructure that must be built is unprecedented, and we believe this is the most important problem we can focus on.

Openness fundamentally affects a lot of the core institutions in society - the media, the economy, how people relate to the government and just their leadership.