Stolen Camera Finder by Matt Burns is a simple website that can track down a lost or stolen camera by searching online for the camera’s serial number in the Exif data embedded in many digital photos. The site has a growing database of serial numbers mapped to photos posted online–more than one million cameras have been identified.
Every photo you take with your digital camera contains hidden information about both the image and the camera such as the make, model and date. This information, called exif data, can also include a unique serial number which identifies your camera. stolencamerafinder crawls the internet searching for photos, collecting the serial numbers of the cameras that took them. When you use the drag & drop feature, stolencamerafinder reads the unique serial number from the exif data of your photo and uses it to match against serial numbers it has stored.
via Chris Glass