4Chan is, as many would say, the asshole of the internet.

Aside from this, 4Chan is also where every meme ever came from. Many of the things on 4Chan are horrible things (such as goatse). The very few gems that are actually funny make their way to other places on the internet.

This site is home to many Trolls, who use things like goatse and /That Series/ ("Of Warlords and Pleasures"), and other things that cannot be unseen to terrorize other sites through obscene spam. Most of these things are on /b/, which is basically the armory for Trolls. I recommend that, if you feel the urge to visit 4Chan, you leave any religious beliefs, morals and etcetera behind. Also, please make sure there is nothing nearby for you to kill yourself with, becaue you /will/ lose all hope.

Much like the Fight Club, you do not talk about 4Chan. Not ever.

4chan is the nexus of the internet, where everything goes to live and die. Especially famous for begetting the rickroll, SHOOP DA WOOP, and lolcats.

The most famous board is certainly /b/, the random board. After that probably comes /a/, the anime board, and then maybe /v/, the video games board.

...See Encyclopedia Dramatica for where much of 4chan goes to die.

The birth place and the death bed of the internet. It where things are created and where things are destroyed. It is all powerful and knowing and for one to survive in its culture, they must leave behind all previous thoughts of normality. What's happens in 4chan, stays in 4chan, until posted anonymously elsewhere.

4chan is hell. The congregation of all assholes, pedophiles, creeps, hackers, and others on the internet. Memes spout from it, and spread quickly. 4chan is like a gigantic titan that should be either killed or locked away in Oblivion.

The most fucked up,pedophile-infested website on the internet. It is an english-translated pornography imageboard with the japanese form 2chan. its best,more like worst, image board is called /b/, where it mostly contains of child pornography, sexual jokes that aren't even funny, and memes that lose their popularity 5 minutes after it is created. In fact, this website is SO fucked up, that, for example, on subeta, a gaia/deviantart/neopets website, has been hacked by stpid fucking anonymous, a fucking pedophile and moot, some stupid fucking anthro hello kitty ripoff. just because subeta took the longcat (meme on 4chan) meme, so 4chan got all mad and hacked into subeta's creator, keith's paypal and bought 3 playstation 3's and the first season of the fresh prince of bel-air with his money. 4chan also hackec gaia people who used subeta by hacking into a gazillion accounts and posting pictures of dead cats.

4chan fucking sucks.

A place where all the faggots and autists of the internet live and try hard to look cool by trolling.

A shitty site for closet homosexuals with no social life with nothing else than anime, gay porn, spam, retarded threads like "rate my (micro)cock", "need advice about <whatever>", "I hate jews and <whatever>".
Whoever wrote the first definition must have been on crack.