There are much better trolls than the one described here, that are guys using trolling to show a point about a controversial subject. For instance the flying sp

There are much better trolls than the one described here, that are guys using trolling to show a point about a controversial subject. For instance the flying spaghetti monster thing is a form of trolling, and it is a good one. I think that in programming forums the biggest source of trolling is due to clueless people that still want to say something... in the real world they would be put at the door, but you can't do this in a forum, and even after a ban it is too simple to re-enter. The simplest form of protection about this is to associate a cost to username creation in a forum. Even 5$ is enough. This time the ban is a real cost for the troller that will likely stop after the first 5$ rounds. Another widely used form of "cost" is badges, that is, you start with an account that can do very little and it takes time (and a good comportment) to grow in features. However there is the risk of trolls opening N accounts in parallel just to have reserves of usernames, so it is also very important to penalize non used accounts.