The controversy I was apparently alluding to in the 2007 post I quoted yesterday was so earth-shattering that it has its own section in LiveJournal's Wikipedia entry:
In May 2007, LiveJournal suspended approximately 500 accounts and communities, causing what news.com referred to as a "revolt" from "thousands of LiveJournal customers", after a number of activist groups, including one named Warriors for Innocence, reported pedophilic material on its website. ... Most of the backlash was from fan fiction writers whose communities and personal journals were among those suspended, seemingly because they listed interests such as "incest" or "non-con" (short for non-consensual).
It must have been Harry Potter fans that I was ridiculing in my post; pedophilia (e.g. Harry/Snape) and incest (among various members of the Weasley family) have always been popular in the HP fanfic community. (In fact, before she wrote a best-selling series of YA novels containing elements of brother/sister incest called The Mortal Instruments, Cassandra Clare wrote an incest fic starring Ron and Ginny Weasley called ... The Mortal Instruments. If Jonah Lehrer knew anything about Cassandra Clare, he would be so pissed.) It's possible some Supernatural communities might have been affected too -- I wouldn't say that Supernatural fandom is all about incest, but it's probably 90% -- but since the Winchester boys are of age, I tend to think not.
You know, I gotta say, that's one of the things I like about Community fandom: on the whole, there's far less drama associated with it than with HP or the Whedonverse or Supernatural or Doctor Who. That may be due to Community fandom being so much smaller than those other three, but it may also be because Community is a comedy. Maybe discussing comedy just doesn't lend itself to drama the way discussing dramas does.