The world is now awash in data and we can see consumers in a lot clearer ways.

If we compare the two, Facebook is currently a superior place to market a product like Slide. Twitter is more like a general distribution agent. It's like broadcast radio.

I have this massive notebook called IDEAS and another one called PERSONAL IDEAS and another one called CRAZY IDEAS.

As I was getting interviewed by the Wall Street Journal, or some big pub guy, all I remember was that he went off to the bathroom for a second, and they brought out my omelet. The next thing I remember, I woke up, and I was on the side of my own omelet, and there was no one at Buck's. Everyone was gone. They just let me sleep.

The very first company I started failed with a great bang. The second one failed a little bit less, but still failed. The third one, you know, proper failed, but it was kind of okay. I recovered quickly. Number four almost didn't fail. It still didn't really feel great, but it did okay. Number five was PayPal.

I think the hallmark of a really good entrepreneur is that you're not really going to build one specific company. The goal - at least the way I think about entrepreneurship - is you realize one day that you can't really work for anyone else. You have to start your own thing. It almost doesn't matter what that thing is.

If you're building a social product, you're still living in the last century if your product doesn't work on Facebook.