Either seen as a death threat, list, or something random to scare or "reward" people, a chain letter is something that many idiots believe in. It is an epidemic on Youtube and Myspace. Usually, middle schoolers and people without friends forward these, but these letters are annoying as hell generally. If it's not a death threat, it says that it will tell you that if you forward it, that you'll have yourself a boyfriend/girlfriend on Friday.
Person 1: Hey! I just reposted this chain letter on Myspace saying that she'll finaly be mine on Friday!
Person 2: Shut up! Myspace isn't going to decide that for you. Grow some balls now.