I think Bitcoin and porn go hand in hand. There are definitely a lot of porn sites that accept it already, but there are some fairly large networks that are holding out as well...

I think Vorotel is a good example of what can happen when a large payment processor accepts Bitcoin. Hundreds of adult sites began accepting Bitcoin basically overnight with no additional work needed to integrate it.

Get a company like CCBill onboard and there would be even more acceptance in the adult industry.