Most notably, Iwaku has a Mythos, crafted out of countless inside jokes and roleplays GMed by both staff and members. It is currently being played out in the roleplay, Iwaku World . In this case, Iwaku could pertain to the 'world' these characters exist in. Various other 'alternative worlds' exist which also call their own homeplanet 'Iwaku'.
For the sake of clarification, the world in which the mythos plays out is simply called Iwaku World. The Alternate Worlds may have their own names for their home planet or the Iwakuan counterparts as well.