Pedants, the lot of you
Yea, it was not the first (and only arguably the best), poor comment from the author either badly researched or a typo, but unlike the view of many posters this is not a history of digital article (which would be interesting, anyone remember Studiokit from the mid 90s? or the leica S series, again larger than full frame in the mid 90s?).
Stu hits the nail on the head when he brings it back to lenses, although it's not quite as simple as saying over 12 needs better lenses;
. Lots of pixels (to give the definition)
. Physically large sensor (to ensure enough photons hit the pixels)
. Big glass (to allow lots of light in)
This is why the 10Mp £49 ASDA compact is a world away from the 10Mp EOS 400D, there's lots of detailed reasons why (bokeh, circles of confusion) but it all comes down to the three factors above, get lots of light and chop it up into small bits (but not too small or reciprocity and wavelength becomes a factor).
I remain unconvinced by the article, there's a lot of space that says loads of things (some of the example images used were useless) but makes no relevant comparisons or real reasons why the 5DMk2 is so good, I have some great pictures that directly compare images on my 400D and 5DMk2 using both the 70-200 F2.8L IS and 400 F2.8L IS (the 100-400 pictured is a good lens but poor compared to these two) - A Mk1/Mk2 comparison woudl have made far more sense.
It has really undersold the 5DMk2