As far as income goes, there are three currencies in the world; most people ignore two. The three currencies are time, income and mobility, in descending order of importance. Most people focus exclusively on income.

At its core, I don't view Facebook as a social network. I think it could become the driver's license of the Internet. And beyond that, it can become the pipes and the plumbing upon what most of the Internet is built. I think it's very well positioned.

Changing the world doesn't require much money. Again, think in terms of empowerment and not charity. How much were Gandhi's teachers paid? How much did it cost to give Dr. Martin Luther King the books that catalyzed his mind and actions?

I work hard, but in spurts.

Happiness has a very short half-life.

Resolve to do one thing every day that you fear.

There is an infinite selection of things that I could test in life, so I generally will look for a critical mass of word that comes back to me. At this point I have hundreds of friends who are the best at what they do, arguably number one in the country or in the world. I will oftentimes just kind of throw a volley out to people, ask them what they're obsessing on or what they find interesting that's on the fringe. If the same answer comes back a few times, I'm like, "Okay."