Slightly off-topic, but I really think you will enjoy this article: Cooking pot markets: an economic model for the trade in free goods and services on the Internet. From the always wonderful people at First Monday.
[Linus] Torvalds remained in the University out of choice, not necessity. Linux has paid back, because the reputation it’s earned him is a convertible commodity. “Yes, you can trade in your reputation for money,” says Torvalds, ” [so] I don’t exactly expect to go hungry if I decide to leave the University. ‘Resume: Linux’ looks pretty good in many places.”