I have to agree, the organization... the only thing that comes to mind that is close is the SCA and that's an *activities* group. Then there's the the gaming community's large amorphous mass of game data, analysis, and strategies.
Nothing I've come across in all my geek hobbies anywhere approaches the "OCD" or wide variety of skills brought to bear on this hobby. It certainly makes for a fun part of my general cultural studies
But no, I"m not sure I have a good handle on what exactly makes it tick so well.