Features include a blog service, photo albums and forums. Users may download skins and setups for the Opera browser... 

http://my.opera.com/community/

A social software platform providing a small-world network for professionals... 

http://www.xing.com/

Find, connect and keep in touch with friends and acquaintances, post photographs, announcements, and biographies, read community message boards and be informed of upcoming reunions. Free and paid memberships... 

http://www.classmates.com/

A video, photo and journal based community that enables users to program dynamic multimedia communities around music and pop culture topics... 

http://www.buzznet.com/

A live entertainment community allows users to communicate with one another through a two-way web cam interface with interactive broadcast controls. Also offers access to content such as video clips, live web cams, and games... 

http://www.broadcaster.com/

Advogato is a community site for developers of free software... 

http://www.advogato.org/