On StolenCameraFinder.com “use the serial number stored in your photos to search the web for other photos taken with the same camera”.
Here’s how it works:
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.