Chess History – Come discuss the past.
Chess Talk – General discussion.
Computer Chess Club – Web-based moderated discussion forum aimed at keeping the posts on-topic (computer chess). Very active.
Correspondence Chess Message Board – Another web-based board, this one dedicated to CC. Also very active.
Chess Thinker’s Forum – Another discussion board hosted by the Computer Chess Club people.
Kasparov Chess Message Boards – The KC site offers discussion boards divided into a half-dozen or so topics.
Yahoo! Chess Message Board – More general discussion.
Chess-L – E-mail based chess discussion list. From this page you can sign up, and also look at the list archives.
Chess Chat – Another chess mailing list. Active.
Chess Reviews – Discuss chess software. Moderated by Bob Pawlak, creator of the ChessReviews site.
Warning: Many crazy people.
Usenet FAQs – FAQs for rec.games.chess newsgroups