The forum I run only bans IP addresses caught posting link-spam. Which, admittedly, asymptotically approached 100% of Tor exit nodes before I instituted more rapid ban-expiration. I added faster ban-expiration after hearing from some of my privacy-conscious users that Tor had become unusable for my forum.
> Most forums ban all Tor exits.
So running an exit at home to coverup for posting on a forum that bans all Tor exits, that makes no sense.