"Two services that search web images for the serial number of the cameras that shot them are helping to re-unite owners with their lost and stolen cameras. Both work by looking for the serial numbers embedded in images uploaded to services such as Flickr. CameraTrace, which costs $10 per camera, now includes a monitoring service that updates you if new images are posted. You also receive an identification tag for your camera, to help recover it if lost, rather than stolen. Stolen Camera Finder, meanwhile, requires only that you drag-and-drop a file from your camera for it to read the EXIF and start searching for public photos with their metadata intact.
Although hardly flawless (neither can search Facebook because it strips EXIF data and some cameras, including all Sonys, don't include their serial numbers), both sites have led to photographers being reunited with their cameras."