"It's really all about Newtonian physics. Big cameras give you a steady shot because they have mass, but small cameras don't. You could solve this by strapping a 20lb brick to your DSLR, but that would look silly. So by adding weight to the bottom of a monopod, the camera becomes more steady, but only on two axes .... and there are three. So you move the weights out to the end, giving you stability on the third axis."
The video is pretty cool and looks pretty stable for $55-$65. Might get one instead of paying quadruple that for a glidecam. The weight stick on the bottom might be kind of big/bulky for skiing, but for just making films/shorts, ect. could be good.