Much technical information gets exchanged on Gutters . Once you find the name of a mailing list, you might want to search the web for the real info on that mailing list. Just in case I've forgotten to list some good discussion groups, choose this link to go over to DejaNews and list the comics-related newsgroups they know about. Classic - For the discussion of golden and silver age comic books. Lots of off-topic ads.
Useful traffic is pretty much dead.
If you can't get news, try Dejanews Alt. Also a filk or two. Small Press Comics Chat - A FAQ and a Prayer. Closure, the Comics Creators Journal - If you're a published comics creator, there's a mailing list called Closure for the discussion of issues relating to comic book creation. Larry Dempsey's Comic Book Inking Survey - It's a survey on the tools and techniques inkers use, with answers from over a hundred professional creators.