Marketing is about values. It's a complicated and noisy world, and we're not going to get a chance to get people to remember much about us. No company is. So we have to be really clear about what we want them to know about us.

It can improve the customer experience if ads are done in the right way and we also want to make sure that we don't do anything that causes our prices to go up in our retail business.

People influence people. Nothing influences people more than a recommendation from a trusted friend. A trusted referral influences people more than the best broadcast message. A trusted referral is the Holy Grail of advertising.

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.

If you're not doing something that people will remark on, then it's going to be hard to generate word of mouth.

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.