From the Baltimore City Paper, the most complete account I've read of the war between Anonymous and Scientology. An excerpt:
In an e-mail, Doc describes Anonymous as "the first internet-based superconsciousness." Anonymous is a group, in the sense that a flock of birds is a group. How do you know they're a group? Because they're travelling in the same direction. At any given moment, more birds could join, leave, peel off in another direction entirely. A popular picture of sign-waving Anonymous protesters in their trademark Guy Fawkes masks is captioned: "Oh Fuck, The Internet is here."
At the March 15 protest, an anon in his 30s who says he works in homeland security, compares Anonymous to the War on Terror–you can fight terrorists, but you can't fight an idea. Anonymous, he says, is an idea.
As he says this, he's wearing a suit and surgical mask, standing on a street corner outside the Washington Church of Scientology, while someone reads L. Ron Hubbard's military record over the PA system.
A guest blogger at Henry Jenkins' site has more. Whether or not you care about Scientology itself, this is a fascinating study in decentralized, leaderless organization—and in the ways ephemeral online fandom can evolve into something politically engaged.