Always good to clear this up, Willem.
1) This is updated hourly. If you look now:
http://www.amazon.com/gp/bestsellers/videogames/ref=sv_vg_1/103-8762235-3402243
The DS is now destroying everything else, with two SKUs well above any other SKU for any other system. Things fluctuate wildly on an hourly basis.
2) Because of the Wii's unprecedented level of demand, the Wii is unavailable for pre-order on Amazon, unlike most other systems. This can be seen by looking again at the list of hourly best sellers. See how all the other systems say "add to cart" while the Wii says "see all buying options?" That's because the Wii is sold out and cannot be pre-purchased. By clicking on the "see all buying options" link, you get several options -- none of which include buying it new, right now, for 250 dollars.
The only way for Amazon to sell Wiis right now is to sell used/second hand ones (starting at 409 dollars, currently), and so they sell much less in these time frames. When they get a shipment of new Wiis in (Which they sell for 250 dollars), the system usually rockets right back up to number 1.
3) Historically, we've seen that Amazon sales alone aren't especially telling. They aren't useless, but in the past the trends on Amazon have been deceptive if taken as a representative sample for the whole.
