The November issue of Wired has a story about WantedList (warning: adult content), the Netflix of pornography. Believe it or not, it's got a lot of great information about the business side of things, including the churn rate (10%), cost to acquire a new customer ($25, less than Netflix), startup cost ($200,000), number of titles (15,000), customers (25,000) and much more.
The two guys that started it told their parents that they were "...self employed Web consultants."
If you've ever wondered why Netflix has avoided porn, this is just one of the reasons:
A big problem: single guys cancel the service when sex becomes a two-person sport.
The story is not online yet, so if you want to read it, you gotta buy it.