[bhouston]

It is probably very similar to how Ubisoft made Just Dance using the Wii controller. The Wii controller was really horrible in terms of what you could read from it, but if you stored what measurements you got from people dancing properly you could score people against that. Basically there was enough degrees of freedom to identify decent dancing to a degree and if you hid what was actually going on people bought it. Although it Wii-based Just Dance is horrible compared to the XBox version that used the Kinetic.