I found "The Good Website Guide 2005" while tidying up some books and looking for stuff from the howies library.
I'm always dubious of books about the internet. By the time you get them printed and on shelves, they're in danger of being obsolete.
This book has a section for 'Social Networking' and it lists two main options - http://friendster.com and http://notfriendster.com
How times change...