The Internet Movie Database, a website that records every movie ever released, along with television series and episodes, video games, actors, voice actors, major characters, and so on and so forth. Each movie has its own forums, and these forums are often plagued by Trolls and Sock Puppets -- particularly the "Politics" and "Soapbox" subforums, which are troll-magnets.
Users can give 1-10 grades to movies. After the death of Heath Ledger, many users pre-emptively gave The Dark Knight a perfect 10 rating, while at the same time giving perennial high rankers such as The Godfather a rating of 1. Prior to the release of The Twilight Saga: New Moon the more avid of the Twilight Fan Dumb gave mass ratings of 10 to the film before it even came to theaters, luckily /b/ was there to even it out with a healthy dose of 1s without even seeing it. IMDb's averaging algorithm is designed to compensate for this kind of behaviour to an extent.
In case you are interested, you can consult the 250 top IMDB films list to know which films are near-unanimously acclaimed (or at least have a high consensus about its quality), and the 100 IMDB Bottom in case you want to know about notorious bad flicks. Those lists are in constant update.
Oh, and to remind everyone, we are not trying to emulate IMDb.