A very good point. The Eiffel tower photos will only show up when people are ironically taking photos from the tower, instead of the tower. It's much too big to get a good photo of with normal point and shoot lenses. There will be related hotspots such as from across the river, but lots of random photos on the streets will be of the tower from different angles.

Whereas the Moulin Rouge is tucked into a street, and that street is the only place you can snap it.

A great innovation in camera tech would be to tag the 'main' object being photographed if it is more than xm away from the camera itself. Using GPS for direction, and using some type of algorithm for detecting the main image, I'm sure you could get a decent approximation of the target as well as the shooters location. That would make for some interesting data and you'd be able to sort on landscape vs portrait photos just by examining the GPS data.