Imagine a similar tool for GNOME: We could aggregate click (and mouseover!) data from users and display it on our own systems — not with images, but by highlighting running applications! Doing it for the desktop shell (panel, applets, nautilus) would be somewhat more challenging, given that everything can move around so much. Perhaps the panel could provide a small amount of layout and configuration data to help with visualisation.
The usefulness of raw data such as this is debatable, but gee it’s handy when you’ve got it.