That’s not funny!

In December 2007, Chris Forcand was arrested in his Toronto apartment and charged with luring an underage girl, possessing a dangerous weapon and other related offences. Forcand, then 53, had posted nude photos of himself in Internet chat rooms and tried to proposition young girls. After some of those lurid conversations were sent to members of his church, Toronto police’s Child Exploitation Section was called in. Forcand was later sentenced to 12 months. The cyber-vigilantes who uncovered his activities and brought about the arrest did not reveal their identities. But subsequent reports linked them to the Internet group Anonymous, which grew out of a message board site, 4chan.org, that is arguably one of the odder places you’ll find online.

If you’ve never heard of 4chan, you’re probably still aware of some of its actions. Its users have created some of today’s most popular Internet memes, such as Rickrolling, which blasts people’s computer screens with a link to the Rick Astley song Never Gonna Give You Up, and lolcats, those photos of cutesy felines accompanied by broken English captions like “I can has Cheezburger?” (itself an irritating slang called lolspeak). Remember the buzz about the Chocolate Rain song, by Tay Zonday? Its popularity partly stemmed from a joke—channers decided to boost its ratings because of its absurd lyrics and melody; it was eventually covered by John Mayer and others. With more than 300 million page views per month, 4chan can create news simply on the basis of size. When something becomes a trend on the site, it will likely hit your computer screen soon, explains Tim Hwang, a research associate at Harvard’s Berkman Center for Internet & Society.

So what does this cultural force look like? It has been hailed for its comedic genius, criticized for its cruel pranks and online harassment, and named a centre of counterculture by Time, which described it as “raw, sarcastic, bare of any social or political agenda but frequently funny as hell.” Time would know, as it appears to be the butt of a 4chan joke that rigged the voting of the magazine’s “World’s Most Influential Person” online contest, according to several reports. The founder of 4chan, called “moot,” is this year’s winner; he beat out Barack Obama and the Dalai Lama. (Time wouldn’t confirm or deny the hack, but the results speak for themselves. The first initials of the top 21 candidates spell the phrase “Marblecake also the game.” Marblecake is the name of a 4chan discussion on Scientology, and a sophomoric sexual reference.) This bit of computer mischief is emblematic of the site, whose users have been accused of everything from satirical scams to cyber-terrorism. In other words, 4chan is a powerful microcosm of all the charm, possibility, chaos and destructiveness of the Internet.

The people who drive the site aren’t exactly society’s heavy hitters: the biggest demographic appears to be 12- to 17- year-old boys, according to Quantcast.com, a site that measures digital traffic. Their idea of a good time is pretty much what you might expect from teenagers, especially bored, sexually frustrated ones: postings full of swear words and pornography are common. But so are racist slurs, as well as rape jokes, homophobic curses, and toilet humour. The aim is to get a rise out of the audience—to create “lulz,” a corruption of “lol” (short for “laugh out loud”) that relies on the joy of upsetting someone.

Sometimes, as in Forcand’s case, users seize on a cause. In February, channers found a video of a cat being physically abused on YouTube. With some Internet sleuthing, they found the identity of the teenager who’d allegedly posted it. They phoned the local police, who arrested the culprit—a boy from Lawton, Okla.—and took the cat to the vet.

Anonymous has also gone after the Church of Scientology, hassling members and hacking into computer accounts. According to the church, this ongoing global campaign, called Project Chanology, has resulted in 41 death threats, 56 bomb and arson threats, and 40 incidents of vandalism against staff, members or facilities. Last week an Anonymous member, 19-year old Dmitriy Guzner of New Jersey, pleaded guilty to hacking charges; he faces 10 years in prison.

Some of the pranks have a political purpose: the 4chan poster who allegedly hacked into Sarah Palin’s email account during the U.S. presidential campaign was identified as David Kernell, the son of a long-time Democratic state legislator in Tennessee. He will face trial next October. At other times, the harassment is senseless. One of the most brutal bullying campaigns involves a Minnesota family. In the spring of 2006, 13-year-old Mitchell Henderson of Rochester, Minn., killed himself with his parents’ rifle. The reason for the tragic suicide wasn’t clear, but after his death, someone on 4chan saw an entry on Mitchell’s MySpace page referring to a lost iPod and decided that was the reason he had killed himself. Joke videos re-enacting the suicide appeared online, and someone left an iPod on his grave, taking photos and posting them online. Prank calls by boys pretending to be Mitchell’s ghost were made to the family, and continued for a year and a half, said Mitchell’s father, Mark, an IT executive, in an interview with the New York Times. “What’s unbelievable is that this is still going on,” explains one of Mitchell’s relatives, in a phone call with Maclean’s. “These people are still trying to discredit him.”

Unlike most Web forums, 4chan does not filter salacious or vulgar material. Almost anything, no matter how depraved or cruel, can make it onto the message boards, although there is a ban on child pornography. Since it doesn’t require user names or registration, most people are automatically given the name “Anonymous.” And “lulz” humour is intensified by anonymity, which several studies show can shift behaviour and even morality, says Shaheen Shariff, a professor of education at McGill University. Consequences in the real world seem remote, and some people become less empathetic, “more aggressive.” Tim Hwang once witnessed the transformation in reverse. In January, the Harvard associate organized a New York conference about Internet culture. Several Anonymous members showed up in Guy Fawkes masks—a look inspired by the cult comic and film V for Vendetta—and began heckling a speaker. As soon as one of the hecklers was brought to the front and given a chance to speak, they all calmed down, Hwang says. But as it is, a number of violent “jokes” on 4chan have spiralled out of control and police become involved. There have been at least four such cases, in Australia, the U.S. and Sweden. In one instance in February 2009, threats of a school shooting resulted in the evacuation of a school in Eskilstuna, Sweden, and the arrest of a 21-year-old man.