The Flickr Camera Finder homepage tells you which cameras are most popular among its users and provides links to camera-specific image galleries.
Good information to have, if you’re looking for which cameras are the most used.
You may not know about Flickr Camera Finder, but it’s an amazing feature that uses the “Exif” data from all images uploaded to the service and creates analytical tools based on that information.
Apparently, if I delve into the data, I can find info on DSLR lenses too. Might be worth looking into.