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.

With a generation of younger folks who have thrived on the success of their companies, there is a big opportunity for many of us to give back earlier in our lifetime and see the impact of our philanthropic efforts.

Facebook is really about communicating and telling stories... We think that people can really help spread awareness of organ donation and that they want to participate in this to their friends. And that can be a big part of helping solve the crisis that's out there.

I mean, we've built a lot of products that we think are good, and will help people share photos and share videos and write messages to each other. But it's really all about how people are spreading Facebook around the world in all these different countries. And that's what's so amazing about the scale that it's at today.

Helping a billion people connect is amazing, humbling and by far the thing I am most proud of in my life.

When you want to change things, you can't please everyone. If you do please everyone, you aren't making enough progress.

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.