This report claims that more people were shopping online for an XBox 360 Thanksgiving weekend than the Wii or the PS3. It must be true, they have a graph:
The weekend before Thanksgiving, Nintendo sold 400,000 Wiis. Nintendo has sold an estimated 1.2 million Wiis in the 16 days it has been on the market. The XBox 360 has sold 8 million since launch.
If you go to the original blog post you get a second graph:
Obviously, lots of people were willing to be an XBox 360 for $100 -- even though only Amazon had the offer and that offer was extremely limited.
The reality, then, is a one day -- or one hour -- spike in traffic consisting of people who would buy a 360 for $100, but not for its actual retail price of $300 (without a harddrive or game). What's most amazing is that anyone was looking for a Wii online during the launch. As far as I know, there were no Wiis available from online retailers on launch day -- everything was presold. Amazon is still sold out. Target is sold out. Best Buy is sold out. Toys R Us might have some.
Bottom line? Microsoft did a nice job of stealing some Wii thunder, but only by selling 1,000 consoles at a huge loss.