Warning posted to anonymous forum 4chan before Oregon shooting

The night before the Oregon school shootings that left 10 people dead, including the gunman,someone wrote a post on the anonymous online forum 4chan, warning, "Don't go to school tomorrow if you are in the northwest."

The FBI is investigating whether the shooter,Christopher HarperMercer, was the person who wrote the 4chan post, and is looking into his other social media accounts, as well.

Police said thatHarperMercerleft behind writings in which he ranted that other people thought he was crazy, but that he was the sane one. He also complained about not having a girlfriend.

The boardon 4chan where the post appeared is one where men who identify as "beta males"lament their inability to fit into mainstream society, to make friends and, specifically, to get girlfriends.

Completely anonymous

Members of 4chan can post to the online forum completely anonymously, without even a username attached to their posts.

"You can be anonymous in the sense that your identity does not persist," said Aime Morrison,a professor of English at the University of Waterloo in Ontario, specializing in digital communication.

"Unlike Facebook's real name policies where it's always intended that a legally named individual is visible behind every post, 4chan does not have that as a core value," she said.

Posts on 4chan are also deleted after a few days, so there's no permanent record on the site itself although archived copies do exist.

The result is what's been called one of the "darkest corners of the web,"where rules of morality and responsibility do not apply.

The nude photographs stolen from Jennifer Lawrence's cellphone were first posted there. Two years ago, a university student in Ontario live-streamed his suicide attempt as 4chan members egged him on.

An MIT studyestimated that4chanhas 7 million users, but it may be losing some to competing forums.

4chanhas few rules: no child pornography, no encouraging or organizing illegal activities. But even those are too restrictive for some people, who have set up their own "chans" without such rules.

Users mostly young and male

"The core constituency of 4chan is internet aficionados, so people who tend to have a bit more technical skills, people with a prankster-ish attitude towards life," said Morrison. "It's a largely young and male demographic and it always has been."

While the anonymity of the forum does lead to examples of anti-social behaviour, it also fosters a weird, irreverent creativity.

"All of your favourite cat memes at some point probably originated on 4chan," said Morrison.

"There's this idea of free-wheeling, consequence-free internet where serious things aren't happening. Silly things are happening. People are making jokes. It's for the lulz. I think that's the founding ethos of the site," she said.

"It just turned into the space that it is now, where cat memes and violent hate speech are uneasily co-existing."

Removal of inhibition

Morrison said the anonymity and, in some cases,removal of any kind of identity at all, breaks down users' normal filters for saying or doing things that are socially unacceptable.

"Being anonymous on4chanallows for the disclosure of these really violent fantasies," said Morrison.

"It's a removal of inhibition in the same way that drinking alcohol often makes us say things that are a lot ruder than we would say when we are sober," she said.

"When we talk to people on the phone, we tend to be ruder than when we speak to them in person. When we send them emails, we're even ruder than we are on the phone. And when we send anonymous complaints, we really let rip," said Morrison.

Morrison said it's dangerous to dismiss anonymous threats posted to 4chan and other online forums as "just the internet."

"Just because something is anonymous, it doesn't mean that it's not serious," she said."What happens online is very consequential to what happens in the real world."

The FBI is certainly taking threats posted onlineseriously. Campuses in Philadelphia this week were warned of a threat of an attackposted on4chan,and inspired by Christopher HarperMercer's massacre in Oregon.