Everything2
Aims to catalog all human knowledge and show the interconnections between all the people, places, things, and ideas.
http://www.everything2.com
Google PR:
Meet Up
Connects people around topics of interest locally.
http://www.meetup.com
Google PR:
The Well
Pioneering online community known for engaging conversation and intelligent debate. Features more than 260 conferences ranging from technical and specific to abstract and surreal.
http://www.well.com
Google PR:
Waferbaby
Budding web community with content created by the users.
