The first time I heard about 2012 was in 2000 after a major train crash in Lillestrøm, Norway.
In a TV program later that year (I think), one of the passengers said had seats in the front of the train, but he didn't feel good about it and sat down at the back instead. It was a program about said guy and his belief in UFOs and the extraterrestrials. He claimed, among other things, to have an implant and agreed to do a x-ray to find it. Of course the x-ray didn't show anything, but he claimed the implant wasn't made of a metal known to man

Anyway, he brought up 2012 because he was convinced that was the date when humans take the next step in "evolution". Some of us would then "upgrade" into higher beings depending less on our physical bodies (like grays). It would be mostly young people (everyone born after a certain date was "star children", ready for upgrade if you will), but also elderly of course.
so according to him (and his followers and the ones he himself followed), 2012 would not be the end of the world or humanity, just the end of our current state.
messy post