I added this feature a bit ago which is very useful for viewing exactly where users are clicking our community website.
You can download and install on your own website here: http://www.labsmedia.com/clickheat/
Also there is a very interesting pay service that offers similar that I have considered buying for the community: http://crazyegg.com/
Really the same thing can apply to multi-touch software where as we would have to log each touch or gesture event and then render the collected data like clickheat does (I’m sure M$ is doing this already)
What could we do with this data?
Would be interesting to see a real-time version…