The Minus World
From Mario Fan Games Galaxy Wiki
Minus World is an offshoot of the MFGG Forums created in November 2010 with the social engineering of DJ Yoshiman and run by Kyori and some other folks.
Forum Creation
The official reason for Minus World's creation was so MFGG's own forums could return to a game development-orientated focus, as the majority of the community was interested mostly in chat and not so much in game dev.
This is more or less, a nicer and more political method of saying "to kick all the trolls out of MFGG".