The Wii is still flying off shelves for multiple reasons. Nintendo has created a product that is successful outside the gaming community. People who normally would not play games are interested in the Wii. That leads into reason number two. Superior marketing. Nintendo has done a great job of marketing their product and hitting the different demographics. Third, motion controls. Whether it's the remote and nunchuck or the balance board, Nintendo created a system that can get game players off the couch, which has helped with it's appeal. Combine that with demand that Nintendo can still not meet and games packed with peripherals, you have a product that when people see one on the shelf they feel compelled to buy it.

It's a fad. Every fad sells like hot cake.

Because it prints money.

Because it has "Nintendo" in it.

seconded

The Wii is fresh and different on the eyes of the mass market.Later they buy the console and are unhappy (few and crap games ,it doesnt track your movements ,etc) but while the machine keeps attracting people with its marketing and those people buying their lot (Wii Fit,Sports,Play for the wiimote,some Wii music,Mario Kart Wii) the hardware and those selected games will keep selling .

This.

It also explains why the nintendo gamecube sold so well.

It sells because people like my parents and all 3 of my sisters want one, then you get the lapsed gamers, the Nintendo fans, and hardcore gamers who want something to compliment their other system(s). It appeals to more people than the other systems thus making it sell like hotcakes.

 Also explains how the Virtual Boy bitch smacked the PlayStation.

Interesting the only comment about the games is that they come packed with peripherals. Honestly although I purchased a Wii and WiiFit last week for my wife the only person in the house that has any interest in it is my wife.  Kids and I have plenty of fun with our 360.  She can have her little workout system.