The reason I didn't post the website, it it's soemtimes reffered to as "The darkside of the internet". The reason for that is, it's completely anonymous, so it brings people in who post some things that people from outside their community may be offended.
However when good needs to be done some of the better people on there come through, and do good. Someone once posted a video of their cat being abused on YouTube... Some people on that website tracked him down from the colours of his curtains in the video, found MySpace pictures that matched evrything in the room, and forwarded it to the police.
They've also taken out the F.B.I website on numerous occasions, but most recently to protest the Mega Upload removal. Which probably isn't the best thing, but I hate the way the F.B.I treated Kim Dotcom and Mega Upload.
It's rival website Reddiit is a much happier place, Reddit is the front page of the internet, I will happily post a link to it, but click it at your own risk, as you will end up spending hours on there:
http://www.reddit.com/
Some fantastic things on Reddit, including soem fantatsic "Ask Me Anythings" from celebrities to some fascinating people!