Of course, but I have to say that I wasn't able to find an introductory document explaining the whole stuff from the beginning.
There is no such thing, because there is not one beginning. “Fonts” is far too generic a concept anyway, and can probably not be covered within one single document (actually it can, but then it's one thousand pages thick). I still find that mfonts.pdf is a good starting point for most uses, though.
Nothing of course :) I was joking. But as the first page of the wiki is the starting point for many beginner, well, I would say that the second paragraph is misplaced.
Feel free to modify it, then. It is a wiki.
Starting from its title it seems to suggest that mark IV is what you need in order to run ConTeXt, so go and download it.
I think the ConTeXt community can deal with that small amount of publicity and incentive so I don't agree; but again, this is a wiki, every constructive contribution is welcome. The “What is ConTeXt?” article could be enhanced a lot, anyway. Arthur