We help Chinese companies grow their customers abroad. They use Facebook ads to find more customers. For example, Lenovo used Facebook ads to sell its new phone. In China, I also see economic growth. We admire it.

Advertising works most effectively when it's in line with what people are already trying to do. And people are trying to communicate in a certain way on Facebook - they share information with their friends, they learn about what their friends are doing - so there's really a whole new opportunity for a new type of advertising model within that.

I think there's confusion around what the point of social networks is. A lot of different companies characterized as social networks have different goals - some serve the function of business networking, some are media portals. What we're trying to do is just make it really efficient for people to communicate, get information and share information.

I think we basically saw that the messaging space is bigger than we'd initially realized, and that the use cases that WhatsApp and Messenger have are more different than we had thought originally.

I think Facebook is an online directory for colleges... If I want to get information about you, I just go to Facebook, type in your name, and it hopefully pulls up all the information I'd care to know about you.

We're a community of a billion-plus people, and the best-selling phones - apart from the iPhone - can sell 10, 20 million. If we did build a phone, we'd only reach 1 or 2 percent of our users. That doesn't do anything awesome for us. We wanted to turn as many phones as possible into 'Facebook phones.' That's what Facebook Home is.