Without wishing to appear negative, I do find it odd the way that a technical crowd react to these online demos. Would you have found this impressive if it was a compiled executable? Because this is just the same thing, just running slower because it's on the web. It's not technically novel in any way. If you're curious about the algorithm, then take a look at the presentation 'Advanced Character Physics' by Jacobson…
This is what I don't understand - a lot of these WebGL demos as well are largely equivalent (minus some pixel shader stuff that couldn't be done back then) to OpenGL stuff that was being done back in 2000.
People wanting to port stuff to new domains?
Excitement about the web being a feasible platform for running 3D stuff?
People learning about old stuff for the first time and doing experiments with the language available to them?