I don't think an adult forum would be good, most of the members would be guys, sausage fest!
Adult Blogs... thats a sure way to get yourself into legal trouble. Gotta make sure all the sites you link are legit, gotta make sure you arent posting things that other people don't want posted, also, people will probably want a forum with it and you might get user submissions of underage girls. That puts YOU at legal risk. You need like a high priced lawyer to run that crap, because the type of people you will be dealing with arent to be trusted. Bad bad bad.