1. A hellbanned user is invisible to all other users, but crucially, not himself. From their perspective, they are participating normally in the community but nobody ever responds to them. They can no longer disrupt the community because they are effectively a ghost. It's a clever way of enforcing the "don't feed the troll" rule in the community. When nothing they post ever gets a response, a hellbanned user is likely to get bored or frustrated and leave. I believe it, too; if I learned anything from reading The Great Brain as a child, it's that the silent treatment is the cruelest punishment of them all.
   I've always associated hellbanning with the Something Awful Forums. Per this amazing MetaFilter discussion, it turns out the roots of hellbanning go much deeper – all the way back to an early Telnet BBS system called Citadel, where the "problem user bit" was introduced around 1986. Like so many other things in social software, it keeps getting reinvented over and over again by clueless software developers who believe they're the first programmer smart enough to figure out how people work. It's supported in most popular forum and blog software, as documented in the Drupal Cave module.
   (There is one additional form of hellbanning that I feel compelled to mention because it is particularly cruel – when hellbanned users can see only themselves and other hellbanned users. Brrr. I'm pretty sure Dante wrote a chapter about that, somewhere.)
2. A slowbanned user has delays forcibly introduced into every page they visit. From their perspective, your site has just gotten terribly, horribly slow. And stays that way. They can hardly disrupt the community when they're struggling to get web pages to load. There's also science behind this one, because per research from Google and Amazon, every page load delay directly reduces participation. Get slow enough, for long enough, and a slowbanned user is likely to seek out greener and speedier pastures elsewhere on the internet.
3. An errorbanned user has errors inserted at random into pages they visit. You might consider this a more severe extension of slowbanning – instead of pages loading slowly, they might not load at all, return cryptic HTTP errors, return the wrong page altogether, fail to load key dependencies like JavaScript and images and CSS, and so forth. I'm sure your devious little brains can imagine dozens of ways things could go "wrong" for an errorbanned user. This one is a bit more esoteric, but it isn't theoretical; an existing implementation exists in the form of the Drupal Misery module.

Posted by Jeff Atwood