People can live without a Facebook account: my 13-year-old daughter has cancelled her account because it's not cool anymore.

I don't have any great ambition to go out and make money. But I am still fascinated in starting up businesses and starting it in a way and running in a way that I want to do it.

Birthday Alarm was a very simple site based on being reminded of your friends' birthdays.

If you are going truly viral, you don't need press. I mean, MySpace grew for a very long time without any press.

I wanted to build something that was a system - that was mechanical and would propagate itself like a virus. I needed a way for it spread from person to person, and the best way to do that was trying to get someone to get their friends to sign up.

I built websites for myself. I didn't want to work for anyone else. I came from a science background, so I approached things fairly analytically.

When I was a kid, I really liked playing chess, which is pretty geeky; I just enjoyed it - thinking, exercising my mind. And I found computers to be like an eight-hour day chess game.