I will admit that I have only the foggiest idea of what DirectX does. I know you use it in games, and I know that the higher the version number, the better the results. But in my games I never really could tell the difference, mostly because I don’t play graphics-intensive games. (I tried turning on DX10 graphics in DDO, but couldn’t tell there was a difference). Still, the video is pretty nifty.
Edit: So this is kind of pissing me off. Videos keep breaking. Is it because of WP.com’s security policies, or because of Posterous? I honestly can’t tell.