Chat-Forum - Provides free java based chat rooms.
Cyber Survey Engine - Create surveys on your site.
Everyone.net - Add chat rooms and customizable communities to your website for free. (****)
HearMe - Add a voice shat room to any site.
Inside The Web
- Message board service from Looksmart with over 70 topics.
PForum - Custmoizable message boards from MercuryWare.
Suite101 - Discussions, articles, message boards and resources in a variety of categories.
vBulletin - Add and customize message boards on your site. (****)
What Helps - Set up or use online communities on your site.
World Crossing - Offers conversation and threaded messages public forums.