While perusing the net for some information for a biology paper I had to write last month, I came across what I think in my experience is the worst forum on the internet. It's a site on human cloning, and seems to be quite official, having bagged the name "The Human Cloning Foundation" to sound as if it stands for something. The reason why I think it is the worst forum I have ever seen, is because it contains the worst sterotypes of forum goers, and has practically no administratory prescence.
At first glance you will see the thoroughly cubist approach to forum layout, which looks like the family tree of some 18th century French noble. Then there is the inane subject matter being covered in the threads, far removed from the purpose of the forum.
The sterotypes are pretty classifiable as per that comic artist (i forget who) who made charicatures of all the forum and IRC personalities.
A few I saw were:
Christian Soldier - self explanatory
Belloid - rabid athiest/ultimate logician
Logan H/Kyle (might be same person :allnight - troll
Lonley_inoccent455 - ditzy idiot girl
See if you can identify any more and share similar forums.