The primary things that people do on the Facebook is they use it to share with their friends and the people around them and their community, and they use it to keep in touch with people.

The companies that work are the ones that people really care about and have a vision for the world so do something you like.

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.

In a recent survive of Millennials around the world asking what most defines our identity, the most popular wasn't nationality, ethnicity or religion. It was "citizen of the world." That's a big deal. Every generation expands the circle of people we consider one of us. And in our generation, that now includes the whole world. This is the struggle of our time. The forces of freedom, openness, and global community against the forces of authoritarianism, isolationism, and nationalism - forces for the flow of knowledge, trade, and immigration, against those who would slow them down.

When I'm introspective about the last few years I think the biggest mistake that we made, as a company, is betting too much on HTML5 as opposed to native... because it just wasn't there. And it's not that HTML5 is bad. I'm actually, on long-term, really excited about it. One of the things that's interesting is we actually have more people on a daily basis using mobile Web Facebook than we have using our iOS or Android apps combined. So mobile Web is a big thing for us.

If you think about companies that were built in Silicon Valley, a lot of them early on were chip companies. And now the companies that are there, like Apple, are much more successful than any of the chip companies were.

Berlin is one of my favorite cities in the world. I feel like the energy is very youthful. It has such an important history, including its recent history of unification.