I think he was referring to the technology, as in the hardware.

To do this stuff properly, you often need big expensive equipment, so the real question is what they are doing to achieve results using cheap hardware.

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.