Sure. Amazon is a shitty indicator of sale but by tracking stock we can at least roughly calculate if sale keeps momentum or not. Regards PS2... Fact it outsells X360 is good enough for me as for now.
BTW: It's pretty easy to ignore threads. Really. Personally I've never read any of hundreds posts in Brawl topic... I could spam about shitty Pikimin characters all day though
One of the biggest problems with Amazon (and most retailers) is there sales data on its own is not very good for generalizations ... The only retailers that really work well are large established retailers that (generally) do not offer promotions to their customers (Walmart).
Its obvious that over the past couple of weeks the Amazon sales have disproportionately favoured the PS3 being that the PS3 outsold the Wii on Amazon (and crushed the XBox 360) while, based on VGChartz data, the Wii outsold the PS3 by a wide margin (and the PS3 and XBox 360 were close). Simply outselling the XBox 360 on Amazon is not necessarily a sign that the PS3 would have outsold the XBox 360 in general. Even the PS3 selling better on Amazon than it did before the price cut is not necessarily a sign that the PS3 is selling better in general; from my very limited understanding, Amazon is running a promotion where you get the Blu-Ray remote and an additional Blu-Ray movie with your PS3 which may make it a better place to buy it than every other online retailer (meaning sales where shifted to Amazon rather than actually increased).
Essentially, the best way to track the PS3's increased performance would be to watch NPD mothly data (or vgchartz data) ...