tools for real time visualization on the web

hey all,

I started writing some software to support real time visualizations on the web. For example, showing a list of people currently viewing this page, and where they go when they leave. I'm wondering if anyone has a favorite tool for this kind of thing.

I also put up a survey at http://resisttheb.org/middleman/survey/

It's anonymous and shows you how your responses fit in with everyone else's.

I'd definitely appreciate your thoughts in whatever form.

Brien