Radeon is somewhat close...
Most bans are that of username, so say I got banned (have 4 times before) they ban the username Paulson, and sometimes even my email address. (This is then transfered into the database, where if the user logged in as paulson tries to post, they can't, because the database server denies permission. Same with email.)
If I'm really a pissant, and they know my IP address, which they do, they can ban it.
If you do get banned, you get a wonderful message that states:
You have been forbidden to post/reply or edit a message in these forums.
