It has been created from pictures submitted to the Panoramio website. These pictures are all coded with the location where they were taken, and this information is then analyzed to create a color coded picture density map of the world, showing the most and least popular places for picture taking.
To a certain extent, the results simply mirror population density, but it provides an interesting thing to briefly look at.
Recognizing the correlation between population density and picture popularity, a second overlay was also created showing the world’s most interesting remote places. Whereas Europe scored max in the regular picture popularity analysis, places in South America, Asia, and even my home country of New Zealand (is New Zealand really remote?) scored high in this second analysis.
More details and map links here.