Ultimately this is the sort of thing that is utterly fascinating to me, but since a) it gives me no reason that I _shouldn't_ believe it (corollary: mentions no competing viewpoints), and b) I have no expertise at all in the field, I have to assume that I shouldn't go around telling everybody that I know why Europeans are the whitest people on Earth, just yet.
The one presented fact that I'm _not_ totally solid on is, I'm not sure that prehistoric and ancient art are sufficiently solid to provide a date by which we can assume Europeans were white.
The assumption that cave art conventions reflect actual pigmentation is pretty shaky. The egyptian statue reference is just wrong - there's a long tradition of females being depicted as yellow or white versus red or brown for males. This probably has some basis in men engaging in more outdoors activity, but this art is definitely not a photo-realistic rendering. If you want a modern analogy, think the Simpsons! Here's some academic work that mentions the gender conventions:
Since the European conquest of the planet, the fairer skin preference has been projected back onto many other groups of people, but is inherently suspicious given the circumstances within which we've learned about their cultures.
Historically pale skin was prized because rich women didn't work in the fields, they stayed in doors out of the sun. Tans came into fashion with air travel. Only the wealthy could fly to say the Med for their holidays Also I suppose poor slum dwellers didn't get much sun. They only got rickets due to a subsequent lack of vitimum D.
(Note that I have not read this version, nor have I looked at any of the references he's provided - I just noticed the link and briefly scanned through the page)
It would appear the author is an amateur scholar; he provided a very interesting point of view and I enjoyed the read. It would have been comprehensive had he supplied opposing arguments, references, and fleshed out his writing a bit more.
The funny thing is that it contains about as much substance as a "TED Talk," but without better visuals and an animated delivery I have a hard time taking it seriously.
The Wikipedia page on the topic suggests that chimpanzees have pale skin under dark hair and that humans might have evolved sweat glands and less hair for heat management related to a larger brain. Seemed to me that the suggestion there is that paler ancestors became darker in regions closer to the equator (Africa, Australia, Indonesia).
I guess paler people today in Northern Europe may have either had ancestors who became darker and then lightened (as per the Knol piece) or moved out of Africa before their skin darkened to deal with the UV/Vitamin D issue. From memory, it's been suggested that expansion into Europe was around 50,000 years ago.
Interesting story though - have never read a page on Knol before.
The one presented fact that I'm _not_ totally solid on is, I'm not sure that prehistoric and ancient art are sufficiently solid to provide a date by which we can assume Europeans were white.