Big Boards
A list of the largest message boards and forums on the web.

eCultures
A user-generated directory of Internet social communities. All submissions to this directory are subject to a review.

GrabAGroup
Access the Yahoo Groups and download attachments (pictures, movies, zip files) from the messages quickly and easily.

The Alliance of Quality Message Boards
An online community of message boards that are well organized and ran. If you're looking for good topical chat on almost any topic, it'll be here.

The Ultimate Chatlist
Directory of chats sorted by subject.