Two websites that I frequent, Information is Beautiful and Flowing Data, have both posted a heatmap of where touristyness. More correctly, it is a heatmap of people using Panoramio to share their photos.
Bluemoon Interactive, a small codeshop, maps touristiness, based on uploads to Panoramio, a site where people share photos of their favorite places. Yellow indicates high touristiness, red is medium touristiness, and blue is low touristiness.
via World Map Of Touristyness @ Information is Beautiful
via: Map of where toursists flock @ Flowing Data
As you mention above, this heatmap more likely shows the relative popularity of Panoramio rather than “touristiness” (whatever that means). Some hints toward this conclusion are the relative “heat” of Iceland vs. Hawai’i and the HUGE brightness of Europe. Though France looks much dimmer, overall, than the rest of Europe. I doubt its due to tourists avoiding visiting France.