It makes sense for existing communities of interest to create their own 'social networking services' for their users:

Within Fetischmusic.com is FindaFreek.com (also accessible at this separate URL). Says Angel, "Websites like Friendster.com, Myspace.com and LiveJournal.com have opened the door to the huge potential of online community. We have our own Friendster-type engine built into our website, so users can establish personal profiles and search for others by types of tattoos, piercings, hair color/style (Mohawk, etc.) and shared interests. The idea was to build something for the fans. Too many artists build a website to say 'Hey, look at me!' Our approach was to say, 'Hey, look at you!' But this isn't just a fan forum; it's a place on the Internet where anyone who feels like an outcast or is anything other than 'normal' can find solace. It's a home base for anyone looking for a place to feel that he or she truly belongs. This website is for you to express your uniqueness — a celebration of individuality — not a High School clique you must conform to."