The story behind the group Anonymous

The structure and leadership of the group Anonymous, the focus of FBI raids Tuesday in Nassau County and Brooklyn, is to have no defined structure and no stated leadership.

The loosely organized band of hackers and online activists, sometimes called hacktivists, is open to anyone willing to act on the group's causes, which are also loosely agreed upon.

As its name suggests, the group's members act anonymously against corporations, government institutions, and any other organization the group deems corrupt. Its causes include environmental conservation and censorship. Its targets are as varied as the Church of Scientology and the Motion Picture Association of America.

Attacks usually consist of shutting down an organization's website, although Anonymous also has leaked information in the fashion of WikiLeaks, a group Anonymous has acted on behalf of.

Recently, Anonymous released confidential email from executives at HBGary, a technology security company. The group also released email addresses and passwords of employees at Booz Allen Hamilton, a defense consulting firm. Anonymous is affiliated with a blog, presstorm.com, and recently started its own social network, anonplus.com.

The FBI's Gordon Snow, assistant director of the bureau's cyber division, characterized the group as not-for-profit cybercriminals in a statement before a Senate committee in April. It "relies on the collective power of individual participants," Snow said.

The group's most recognized symbol is a headless man wearing a suit and tie. Its statements and dispatches often end with: "We are Anonymous. We are Legion. We do not Forgive. We do not Forget. Expect us."

In a letter to NATO, Anonymous warned against "believing you can behead a headless snake. If you slice off one head of Hydra, ten more heads will grow in its place. If you cut down one Anon, ten more will join us purely out of anger at your trampling of dissent. Your only chance of defeating the movement which binds all of us is to accept it. This is no longer your world. It is our world - the people's world."