Alan Moore/WMG

Alan Moore is Sauron, except he has shitloads of rings instead of one.
That's where he gets his power. The only way to kill him is to flush every single article of jewelry he has down the private toilet of the current DC ceo. Oh, and Grant Morrison is Saruman.

Ron Moore is Alan Moore's Californian-bred clone.
He's got the hair, the last name, the conflicts with executives, and the stuff going on in his stories. But he's definitely gotta work on his beard.

Alan Moore is Rasputin
He used infernal magic to fake his death back in the day and couldn't stand being out of the spotlight for as long as he had been. Not a "wild" guess; more a logical conclusion, but it bears saying nonetheless.
 * I KNEW IT!
 * Wait, this might NOT be true?
 * This page is for Wild Mass Guessing, not for the facts.

Watchmen is a true story. Dan is a surrogate figure for Alan Moore himself.
Not my theory, but my sister's. Has its own theme tune, to the tune of "Dennis Moore".
 * That's silly. Alan Moore is obviously Dr. Manhattan.

Alan Moore, Michael Moore and Patrick Moore are brothers.
They gather for nice brotherly meetings every now and then to play the xylophone.
 * Roger Moore and Mary Tyler Moore are his cousins.

Alan Moore is a transguy.
No reason.

Alan Moore still works with DC Comics (and mainstream comics in general), but uses pen names and actors pretending to be the writers.
He is in fact Geoff Johns, Greg Rucka, Mark Waid, Ed Brubaker, and Grant Morrison (eventually, a man who actually went by the name of Grant Morrison popped up and was assigned to work on Batman).
 * Wait a minute. So your telling me he wrote 52 all by himself?
 * Of course not. He had Glycon to help.
 * I hate to tell you this but that smart Grant Morrison was writing comics before Alan Moore. Therefore Alan Moore is actually Grant Morrison.
 * Grant Morrison was a pseudonym Rasputin used early on, before he settled on the Alan Moore identity. The Morrison side surfaces while he sleeps.

There is a comic industry-endorsed program with the objective of training people to become future Alan Moores.
Since Alan Moore has sweared off doing DC and Marvel, it would be natural for the two to try and get the closest to him. Thus, they just decided to make their own. And naturally, Warren Ellis was the prime result.
 * Couldn't have been a very well run program if that's the best it could do.
 * It's called 2000AD

Alan Moore is Hagrid.

 * Think about it. Both of them are big guys with giant beards who practice magic, for starters. The whole 'kicked out of school for being a drug dealer' thing easily could've been a Memory Charm. Seeing as he was kicked out of Hogwarts as well, he spent some time writing for various comic companies on either side of the atlantic. And if you're wondering how he did this while being Groundskeeper at Hogwarts, I have two words for you: Time Turners!

Those large rings Alan Moore wears are actually cybernetic fingers.
His real fingers are in a jar at DC's main office.
 * Kinda makes you wonder...

V for Vendetta is a Self Insert Fic
Well, almost. Alan Moore hates Film, so it's kinda hard to pin V as a straight-out Author Avatar. But think about it; One man, by himself(Moore) going up against an evil fascist dictatorship(DC Comics), becoming a martyr, and trampling them with the help of his Fan Dumb. The last bit is more Hilarious in Hindsight than anything, since he lacked the kind of fanbase he has today, which is comparable to V's followers.

Alan Moore is actually engaged in a sophisticated public relations campaign to make himself appear to be difficult,moody and unpleasant in a low cost bid to attract attention to himself.
Think about it: Every time it seems like the public is forgetting about Alan Moore,he says or does something that turns the spotlight back on him. Every time. Like JD Salinger,methinks.

Alan Moore is the son of Glycon
He, however, is no longer a demigod, for he embraced true godhood much like Hercules. He's also the real messiah.

Alan Moore is a member of the League of Extraordinary Gentlemen.
He is a character based on the works of HP Lovecraft, who created himself through a maddening paradox, and decided to remove himself and his role in the group from the Graphic Novel version of their chronicles.

Alan Moore is a Time Lord
You know it.

Alan Moore and Grant Morrison are the same person... from different universes!
Moore is from "our" universe, Earth-1, while Morrison is from Earth-2 and was stranded here after Crisis On Infinite Earths. They're both mystic anarchist comic writers with bizarre personalities; the difference is that Moore is very hairy while Morrison is very bald. If you shaved Moore's hair and beard off, you'd find a slightly older Grant Morrison. This is also the source of their legendary rivalry.
 * On Earth-2, the Romanovs never fell and Grigori Rasputin became an important part of the Tsardom. Those Wacky Nazis never rose to power. Hence why he derailed Magneto. Since Grant's an alternate Alan Moore, he's also an alternate Rasputin.
 * Don't forget that both are chaos magicians.

Alan Moore is standing right behind you.
Don't turn around. He really doesn't like that.