I am sure if you would take any other random date, you would find tons of evidence as well for the end of the world. If you just dig long enough, you always find some shit. And also probably harmless phenomenons can be missjudged by people ...
imo it's always the same.. its about scaring people. And as said earlier in this thread, scared people buy things to protect themselves. It is a very predictable mechanism and you can make millions and millions of $$ with it.
I can already now predict you, that we will have end-of-the world phantasies in 2222, 2345, 2500, 3000 etc. as well. Also probably in 2042 the skank-calender will come to an end because someone was to lazy to calculate it any further so we have to assume that the end is near then as well. or probably its just a load of bullcrap, who knows.