The world is changing so quickly, with mobile stuff and different platforms emerging, that I think it's more likely that the biggest competitor for Facebook is someone that we haven't heard of. What that means for us is that we should just really stay focused on what we're doing.

If you actually do something you love it's a lot easier and takes on a lot more purpose.

Think about what people are doing on Facebook today. They're keeping up with their friends and family, but they're also building an image and identity for themselves, which in a sense is their brand. They're connecting with the audience that they want to connect to. It's almost a disadvantage if you're not on it now.

The trick isn't adding stuff, it's taking away.

The thing I really care about is the mission, making the world open.

People will always want more immersive ways to express themselves. So if you go back ten years ago on the internet, most of what people shared and consumed was text. Now a lot of it is photos. I think, going forward, a lot of it is going to be videos, getting richer and richer.

The real question for me is, do people have the tools that they need in order to make those decisions well? And I think that it's actually really important that Facebook continually makes it easier and easier to make those decisions... If people feel like they don't have control over how they're sharing things, then we're failing them.