As most people who use digital cameras knows, the camera records a bunch of information inside every image. This information is known as EXIF, and one of the key pieces of data it records is the camera make and manufacturer. A website known as BigHugeLabs keeps a list they update weekly which tracks the most popular cameras used on Flickr.
When people upload pictures to Flickr, they usually leave their EXIF data intact (ie. they haven’t performed any EXIF damaging editing on the file). Flickr will accumulate all the numbers and do a report every so often - which BigHugeLabs references. You can get the details on the top 10 cameras being used at any given time there.

