It's a term, the dark side, used to describe a a forum that went a bit rules mad, that was obsessed with sending warning emailss and banning people,Luckily the lead villian came to a righteous end, but not before many members had become disiaffected.
Another, sort of rival forum was set up, called the friendly forum, and the dark forum was forced to moderate it's ways and in many ways emulate the friendly forum.This has been a lesson well learned and the friendly bunch stands ready to hand out another lessson should the need arise,
Hope this helps.