An old friend of mine used to say, "the only difference between me and Seth Godin is that he has a shaved head."
Now, he'd have to say the difference was the shaved head and the many bestsellers.
Ankesh Kothari has a great analysis of why Seth is successful.
The most important lessons to learn?
1. Make you and your product stand out. "Purple Cow" stands out more than "Be Different." A shaved head makes you instantly recognizable.
2. Penetrate the market by giving away free goodies. Especially in today's market, people try before they buy. Therefore, get as many people to try as possible!
3. Leverage other people's networks.