What it is

Community on JournalFen devoted to mocking "over-seriousness, ridiculousness, and general stupidity within the various media fandoms," as well as "Self-aggrandizing posturing. Fannish absurdities. Circular ego-stroking. Endless flamewars. Pseudointellectual definitions." I always thought of it as a Go Fug Yourself for fannish behavior--that is, making fun of ridiculous behavior, with the understanding that everyone acts that way sometime. You're not on some kind of permanent shit list if you hit Fandom Wank, although a lot of people react to it that way; God knows that I fully anticipate being wanked there one day if I do anything stupid, and several FW members themselves have been wanked for ridiculous behavior.

A lot of people, however, don't see it that way. A lot of people get really angry about Fandom Wank, and a lot of times I can't blame them. FW was never perfect, but it definitely had a huge jump in membership after Crystalwank, and a lot of people joined the community not really understanding that the point of the comm was much like that of a nature program: to observe, not get involved. At this point, I think there's something like ~~3400~~ 4300 members, and since FW is not a hive mind, individuals will inevitably act like asshats now and then.

Trufax

Has a number of spinoff communities (otf_wank for "other than fandom," fandom_lounge, clairvoyantwank, i_wank for when you yourself are involved, wankitywank for in-house asshaberdashery, hp_cornfield for the Harmonians, fwank_icons, and so on). At some point I realized I'm actually a fandom_lounge mod, so, you know, see you over there.
The place to be for the Potterdämmerung.
Guidelines are here.
FW has a wiki all to itself! Go forth and roffle.

Ground rules

People who are not allowed to post on JournalFen are also, therefore, not allowed to be wanked (read: to have FW entries written about them), on the principle that they can't show up and defend themselves. This includes 1) anyone under the age of 18 and 2) anyone who has been banned from the site.
"Trolling the wank" (acting like an asshat on the journals or boards being discussed on FW) is not allowed. Generally, people are discouraged from commenting at the original site(s), period, once they've seen a FW entry on it. Obviously this is hard to enforce, since a lot of trolls either lurk on FW or post anonymously, but any known member who trolls a wank will be banned, or suspended, or something bad. I forget which. But it's bad.
"Do not link the subject of the wank to FW. This is part of our 'what they don't know won't hurt them' policy. If someone has been wanked, it is simply not cricket to draw their attention to it." Much the way that the Fug Girls don't go call Bai Ling's agent to tell her that she's been fugged (again), you don't run go tell people that you and a bunch of other people are discussing something stupid they did, because that's nasty on an entirely separate, additional level.
Do not link to locked material. This is a big one, and works essentially like this: if asshaberdashery occurs behind locked doors--i.e., on a Livejournal post that is not public--it is not admissible in court, so to speak. If it was ever public and then locked, my understanding is that it's fair game. Anything on a community that is locked but easily accessed by simply joining the community is also fair game. The real key here is the intention of privacy--if it was never intended for public consumption, behind closed doors it's got to stay. This also includes private emails, unless permission is given to quote.
Don't be an asshat. Seriously. The point is to sit back and enjoy the absurdity of a given wank, admire each other's icons and make new ones, and start random squeeful tangents. It's not to persecute hapless fans, post grudgewank, or harass people offline.
Full list of rules here. But those are the big ones.

Famous wanks

Crystalwank

This is the wank equivalent of retiring an MVP's jersey: due to comment coding upgrades, it can literally never be surpassed at 12,000+ comments.

Victoria Bitter and Bit of Earth

AKA "The wank about the charity scammers with the girl who claimed to be the reincarnation of Elijah Wood's cousin, or Merry Brandybuck, or something." Before the Age of Potterwank, before Crystalwank, this was the One Wank to Rule Them All.