When you release the shutter on a digital camera, the camera attaches descriptive data -- date and time, make and model, white balance settings and whether the flash was used. Among the 300 or more types of data that can be attached are Global Positioning System coordinates, pinpointing where the photograph was taken.
I didn't realise that. The link talks about a couple of cameras that implement this feature. I would love to have it just for my snapshots, but I imagine there are myriad potential professional applications.