Check here for all the latest, I will repost as I find them:
| Name | Description/Focus |
|---|
| 43 Things | Tagging |
| Advogato | Free Software and Open Source developers |
| aSmallWorld | European jet set and social elite |
| BlackPlanet.com | African-Americans |
| Bebo | Schools and colleges |
| Blue Dot | Link sharing |
| Broadcaster.com | Video sharing and webcam chat |
| Blurty | Blogs, based on LiveJournal |
| Bolt | General (music and video) |
| CarDomain | Car enthusiasts |
| Care2 | Green living and activism |
| Classmates.com | School, college, work and the military |
| Consumating | "Consumeetings" |
| Couchsurfing | "Couchsurfing" |
| Cyworld | Young South Koreans |
| Dandelife | Collective narratives or "shared biographies" |
| DeadJournal | "Dark" blogs, based on LiveJournal |
| Dodgeball.com | Mobile location-based service, owned by Google |
| DontStayIn | Clubbing (primarily UK) |
| Doostang | Careers |
| Ecademy | Business |
| eSPIN | Teen Dating |
| Facebook | College/High School students |
| Faceparty | British teens and 20-somethings |
| Flirtomatic | Flirting/Dating |
| Flickr | Photo sharing |
| Fotki | Photo sharing |
| Friends Reunited | School, college, work, sport and streets |
| Friendster | General |
| Frühstückstreff | General |
| FUPEI | General (Photo, Video, Music, Games, Event, and Chat Room) |
| Gaia Online | Anime and Games |
| Gazzag | General |
| Geni.com | Families, genealogy |
| GoPets | Virtual pets |
| Graduates.com | School, college, and work |
| GreatestJournal | Blogs, based on LiveJournal |
| Grono.net | Poland |
| Hi5 | General |
| Hyves | General; focus on students and Dutch speakers |
| imeem | Instant messaging |
| IMVU | 3D chat software |
| IRC-Galleria | Finland |
| iWiW | Hungary |
| Joga Bonito | Football (soccer) |
| JuiceCaster | General |
| Last.fm | Music |
| LinkedIn | Business |
| LiveJournal | Blogging |
| LunarStorm | Sweden |
| MEETin | General |
| Meetup.com | General |
| MiGente.com | Latinos |
| Mixi | Japan |
| MOG | Music |
| Multiply | "Real world" relationships |
| MySpace | General |
| myYearbook | General |
| Netlog | European young adults (14-24). Formerly known as Facebox. |
| Nexopia | Canada |
| orkut | Owned by Google |
| Passado | General |
| Phrasebase | Foreign Languages (education) |
| Piczo | Teenagers, Canadians, photo sharing |
| Playahead | Swedish teenagers |
| ProfileHeaven | British teens |
| RateItAll | Consumer ratings + social networking |
| Reunion.com | Locating friends and family, keeping in touch |
| Rimzu | Sociometric rankings |
| Ringo.com | General |
| Ryze | Business |
| Sconex | American high schools |
| Sportsvite | Recreational Sports |
| Studivz | University students, mostly in the German-speaking countries |
| Stumbleupon | Websurfing |
| TagWorld | General (tagging) |
| TakingITGlobal | Social action |
| The Student Center | Teens and colleges |
| Threadless | Custom T-shirts |
| Travellerspoint | Travel |
| Tribe.net | General |
| Twitter | Update friends with your status through SMS, IM, web interfaces |
| Vampire Freaks | Gothic industrial culture |
| Vox | Blogging |
| WAYN | Travel & Lifestyle |
| WebBiographies | Genealogy & Biography |
| Windows Live Spaces | Blogging (formerly MSN Spaces) |
| Xanga | Blogs and "metro" areas |
| XING | Business |
| Xuqa | Colleges |
| Yahoo! 360° | Linked to Yahoo! IDs |
| Yelp | United States adults |
| Zaadz | Social consciousness |
