"During E3, Nintendo gave a presentation to analysts about the company's new offerings and its current status. Reggie Fils-Aime presented the above slide, which shows the startling truth about the Wii's installed base in the United States: in its fourth year on the market, it's larger than the ubiquitous PlayStation 2's installed base at the same point in its life, by a margin of almost five million units. Of course, the PS2 has had a spectacularly long lifespan after that, with Sony announcing 7.2 million units sold just last year.
Later in the presentation, Reggie revealed that around 300,000 units of the black Wii console have been sold since its May 9 introduction in North America, and Super Mario Galaxy 2 is "approaching 900,000 units here in the U.S."
Nintendo just can't stop selling Wiis. This is probably the strangest thing I have ever seen; I have never seen something this popular keep selling after 4 years. It is absolutely crazy, and Nintendo's Wii and DS print money.