As with Google, Facebook was a place that just concentrated a lot of top talent. It's just sort of natural that those people would go on and continue to be successful.
Facebook was a very big mission; it really knocked it out of the universe. It's pretty hard to focus on a small idea after that. You really have to be working on something that you believe will be of similar impact.
Once a few Facebook employees put together a promising idea and start a company, that's very exciting to people. I happen to think being a Facebook employee is really correlated with good ideas.
It was a precondition to leaving Facebook that I wasn't going to start something that was just about chasing money.