A Pandora equivalent for pr0n. Enter/grade a few images you like or dislike, build a profile and "stations" to group similar kinds of content. Maybe these profiles could be condensed into some short-length string--say a Meyer-Briggs type of string (INTP, etc)--that you can then carry with you without having to actually give out personal info, but that says hey, according to this standard, these are my likes/dislikes when it comes to erotic imagery, now gimme the goods.
I've wondered myself about the market for allowing people to drill down through multiple fetishes. the vast majority of sites organize by single fetishes. what if you could input a bunch of fetishes and it would automatically find the videos that have the most tags in common with your search? this would work best with something that supported user tags, so people could find and tag specific elements.
Just sayin'