If you live in an area where there is not a good school, the internet may be the best way to get access to a lot of education material. The same is true if there is not a good doctor - the internet may be the best way to get access to health.

I think I've grown and learned a lot.

Facebook is inherently viral. There are lots of sites that include a contact importer, and for lots of them it doesn't really make sense. For Facebook it fits so well. It wasn't until a few years in that we started building some tools that made it easier to import friends to the site. That was a huge thing that spiked growth.

I started the site when I was 19. I didn't know much about business back then.

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

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.

Nothing influences people more than are commendation from a trusted friend.