I noticed a lot of people stick a list of things they dislike (an anti-interest list if you will) in their bio, and therefore decided to clone the categorization system LJ uses on my own server. You need to do a quick sign up, validate your account (currently by putting a randomly generated string into your userinfo, which the server then checks for, but I'm going to change this to openID once I've got a breather and figured out how openID works), and you're all set to start adding and removing dislikes. The system then produces HTML for you to stick into your bio, which includes links to lists of the users with the same dislike.
Currently the only major downfall of the system (apart from the inevitable bugs in a beta phase) is that it's not entirely automated, and whenever you add or remove an interest you have to go and edit your userinfo yourself. If this kicks off without any major problems, I will, in the future, program in an optional auto-update feature, which will utilize your LJ Password. A lot of people won't like this idea, but remember: it's optional. You don't need to put your LJ password on this system at all if you don't want to.
That's about it. Any suggestions or ideas for improvement, feel free to make.