A fun idea. But a note from the Github page:

At present the only "functionality" is the display of other players locations on the page. That's pretty lame, right? But I'm tired...

True— although I think that's most of it, really. The comment I read that inspired this idea just wanted to see the other players.

And if you really get into shooting stuff, the mayhem creates an excellent illusion of participation :P

I think it's the sort of thing that needs a certain critical mass of players to be engaging... maybe this just isn't the right time.

Looks like it went down overnight, but the server is now running again.