Hi, I've been developing some marketing materials for Drupal that provide examples of Social Networking sites built with Drupal. Examples of Drupal, Newspaper, Library sites in videos: http://blip.tv/file/912733
If you know of other Social Networking sites which should be added please add them to this wiki page.
Social Networks - Social networking for women, Popsugar - 17Million views per month, GoSleepGo - Find an adventure, Connecting business people, Ourmedia, Matador travel - connecting passionate travelers, JustCauseIt-make some good news, OnNetworks-A fresh alternative to traditional TV, IncBizNet-The Networking Community for Private Companies, Asian social network
Social Collaboration: Amazee: Doing things together
Demo Site - http://socialnetworkingwebsites.realtidings.com
user: admin, pass: admin
http://www.athletefocus.com - Action Sports SN
http://www.babelup.com/ for social activism
http://www.chrisbrownworld.com/
http://drupalsn.com - Drupal social networking site about using Drupal for social networking sites (sounds recursive, doesn't it)
http://www.fastcompany.com/
http://www.goingon.com/ - Commercial business that uses Drupal for its own social network and uses Drupal to build social networks for others
http://www.gradspot.com
http://www.i-bloggers.com for bloggers (not working?)
http://www.icommunity.tv
http://www.ifood.tv/
http://island.byu.edu -- elearning social network
http://www.joshuabell.com/
http://www.katdeluna.com/
http://www.lounge55.com private community (not working?)
http://www.lounge99.com for women (not working?)
http://www.mothersclick.com - Social Networking for Mothers (very nicely done)
http://www.mymacroSpace.com for macrobiotic recipes, advice and friends
http://www.natashabedingfieldusa.com/
http://www.ryze.com - business social networking
http://www.silvervixens.com
http://www.swampfox.ws - Southeast Innovation
http://www.terminus1525.ca - Artistic studio community
http://www.theclashonline.com/
http://www.thenursery.com for new and expecting parents
http://www.thestandard.com/
http://www.whatnow.org.uk for a cancer support system
http://www.wheresspot.com
http://thinkingparticle.com - an Indian travellers' hub
Previous posting: http://groups.drupal.org/node/9011