Well, the wiimote needs no explanation.................it's the main controller for the system........everyone has 1, and the games are built around it.
The board and eyetoy comparison is much more interesting: 2 peripherals packaged with their own specific software. Why is the blance board popular, and the eyetoy turned out to be not as popular? I don't honestly know. However, I think that advertising probably had a lot to do with it. I've been bombarded with e-mails from Nintendo, advertising on websites, papers, bus and TV to the point where if I see that green and white box anywhere else, I'll destroy it. The Eyetoy..........I can't recall such a thing happening (does anyone else remember how Sony advertised the Eye Toy?).