Why do so many Christian end-timers believe the world will end in 2012?

I would not ascribe that thinking of a few radicals to an entire group of Christians as a whole. I don't know any Chrstian who believes that. The Bible clearly states that the end of the Earth as we know it, the second coming of Christ, will not happen until everyone in the world has heard the gospel. At the rate us Christians are going right now, that won't be in 2012 ... but I suppose I could have more faith! ;)