A lot of the time the experts, the people who are supposed to be able to tell you what to do, will tell you that you can't do something even when you know you can. And a lot of the time it's your friends ... who tell you you can do it.

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.

It's tough to say, exactly, what things will look like in three to five years, but there's a lot of work to do in just moving along the path that we've already set out.

Advertising works most effectively when it's in line with what people are already trying to do.

At Facebook, we're inspired by technologies that have revolutionized how people spread and consume information. We often talk about inventions like the printing press and the television - by simply making communication more efficient, they led to a complete transformation of many important parts of society. They gave more people a voice. They encouraged progress. They changed the way society was organized. They brought us closer together.

There are people who are really good managers, people who can manage a big organization, and then there are people who are very analytic or focused on strategy. Those two types don't usually tend to be in the same person. I would put myself much more in the latter camp.

Don't discount yourself, no matter what you're doing. Everyone has a unique perspective that they can bring to the world.