Whilst I've started adding information into the EXIF data, I'm not as yet going to go to the hassle of attacking my photos with the ugly stick or watermarking as it is commonly called.
One thing I've found is that the referral logs tend to give a good indication of where people are looking at the images from. Some odd locations too:
http://unjobs.org/duty_stations/fran...ur-cher/photos