I thought about adding this to my site when I had to write the code, bur it might be intersting as an addon in a future release. Add some sections to the database where a person could enter in a zip code or city state pair with a year and then through Flash or other mechanism have an animation of how the class migrated across the world over time.

Ancestry does something like that for geneology and family trees.

That is a neat idea and I will certainly file the idea for future consideration.

Thanks!