On engagement, we're already seeing that mobile users are more likely to be daily active users than desktop users. They're more likely to use Facebook six or seven days of the week.

Why are most chess masters under 30?

Critics worry that if we spend time paying attention to that new kind of media or technology instead of talking to each other that that is somehow isolating. But humans are fundamentally social. So I think in reality, if a technology doesn't actually help us socially understand each other better, it isn't going to catch on and succeed.

Connecting everyone is going to be something that no single company can do by themselves. So I'm really glad that they and a lot of other companies are working on this.

People wait until late in their career to give back. But why wait when there is so much to be done?

We are working hard to build a service that everyone, everywhere can use, whether they are a person, a company, a president or an organisation working for change

I think a simple rule of business is, if you do the things that are easier first, then you can actually make a lot of progress.