Motion means collision detection and keeping the right data structures up to date. AI means things like path finding. Both sets of problems require lots of loops with lots of maths.

I've looked at Copperlicht and it is nice (looks like you work on it?), but still very limited when you compare it to the non-WebGL competition. The demos are all small largely static scenes that can be loaded onto the card and left untouched in memory.

I don't mean to say that WebGL isn't usable or that people shouldn't use it. I was providing a grain of salt to what was a very good write up.

btw. I like the doco for Copperlicht, nice and accessible and the octtree implementation impressed me when I was reviewing Copperlicht last weekend.