Viral Marketing Works - Which Movie Has Done it Best?

Cloverfield did it successfully, the Paranormal Activity films used it to help catapult the first film of that franchise into the record books, and studios have now caught on to how important a well planned viral marketing campaign is in getting their films buzzed about by potential ticketbuyers. Twitter, text messages, Facebook and Myspace pages devoted to alternative marketing - it's all part of the PR game now. In your opinion, what movie did it - or is currently active in promoting their upcoming release - best?

More Film Categories to Vote on in the Readers' Choice Awards