Well this date has more validity as a point where humanity may be fucked. I say that because that's probably the amount of time it'll take for the radiation from Fukushima to significantly contaminate most of Japan and parts of the northern hemisphere. Unfortunately for them, it's not exactly rapture to heaven kind of ending, but rather a slow death from leukaemia, thyroid cancer and/or infections via destroyed immune system.
And then once humanity is gone, god shall say, "I did it for the lulz"