1. Making Potential Users Ask Publicly To Get In
2. The World’s Strictest Invite System
3. Splitting Up Blog And Library Content
4. Having A Strong Point Of View
5. We Don’t Blog About Our Product
6. Link Roundups For Users And Relationships
7. Using Facebook And Twitter Very Differently
8. A/B Testing The Hell Out Of Everything
9. Being Smart About Paid User Acquisition
10. Knowing Just Who The Hell Is Signing Up

"In the old days, getting customers was easy. You could just outspend. You could use brute force to get the word out. Now, thanks to social media, you don't have to outspend. There is a much better technique. It is to out friend. If you can just be friendly enough and get your users to party with you, the rest is really easy. If you don't want to take the time to develop - building like 20,000 to 200,000 close, intimate friends can take a few weeks - then we have the viral model so you can do this really quickly."