Facebook is quite entrenched and has a network effect. It's hard to break into a network once it's formed.

To make an embarrassing admission, I like video games. That's what got me into software engineering when I was a kid. I wanted to make money so I could buy a better computer to play better video games. Nothing like saving the world.

Constantly seek criticism. A well thought out critique of what you're doing is as valuable as gold

Biofuels such as ethanol require enormous amounts of cropland and end up displacing either food crops or natural wilderness, neither of which is good.

If you're trying to create a company, it's like baking a cake. You have to have all the ingredients in the right proportion.

I think there are too many smart people pursuing internet stuff, finance, and law. That is part of the reason why we haven't seen as much innovation.

It was obvious to me that we could never colonize Mars without reusability, any more than America would have been colonized if they had to burn the ships after every trip.