The document categorizes different types of social networks into 6 groups: 1) identity networks like Facebook and Hi5, 2) creative networks like YouTube and Flickr, 3) interested networks like Delicious and StumbleUpon, 4) collaboration networks like Wikipedia and Google Maps, 5) virtual reality/gaming networks like Second Life and World of Warcraft, and 6) peer-to-peer (P2P) networks like BitTorrent. It also discusses how social networks allow sharing of weblogs, wikis, multimedia and more through platforms like Google.