Yes, the first thing I thought after "ooh, neat" was "Are there any portal communities for HTML5 even close to those for Flash?"
Not as big as Flash portals obviously but people love playing the games
I like JS. I'm learning how to use some of its first class functions, and it's really cool! But honestly the only reason I'd play any of those games is because they're written in an interesting technology... not because they were actually more fun than the stuff written in flash.
There's a lot of potential, but the platform isn't quite ready yet.