where his civilizations, including our own

FictionAlley was also separate to some degree and seemed (from what I knew of it) to have a very different fan culture from LJ. And even within LJ there could be separate circles that didn't overlap very much. I think this is kind of inevitable in enormous fandoms — when X-Files was big, it had the same kind of fragmentation. There is a threshold where you just can't keep up on every part of the fandom anymore because there simply aren't enough hours in the day, and I think that's why the fragmentation starts to happen, just to make it manageable. Of course, once it starts, it's self-reinforcing because people get used to their particular space and group of friends.