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.

I'm not as goal obsessed as I am process obsessed.

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.

We just think that there are all these different ways that people want to share, and that compressing them all into a single blue app is not the right format of the future.

People love photos. Photos originally weren't that big a part of the idea for Facebook, but we just found that people really like them, so we built out this functionality.

When we were a smaller company, Facebook login was widely adopted, and the growth rate for it has been quite quick. But in order to get to the next level and become more ubiquitous, it needs to be trusted even more.