I was hunting around to see if Photoshop would offer something similar to a steganography program (embed a copyright notice in a jpg) and came across this thread. I am curious to know about adding the metadata but the url Anita gave came up as a 404 page. Our online store wishes to add copyright information to all of our product images so that if someone blindly steals our work, we can get them.
TinEye, Digimarc, etc all put the responsibility on you to go chase after your images online. There is still no protection. If all the resources of the US government can't touch wikileaks or online gambling sites, what makes us think an artist can effectively track down and prosecute someone for stealing something they failed to reasonably protect in the first place?
These tools do nothing to help you if your image is duplicated offline.
As an online retailer, we don't plan on routinely checking sites everyday or throwing the book at every offender. We just want to be able to have that little extra protection when we find one of our competitors blatantly using an image of a product that we photographed and edited. I realize that a faint watermark is probably the best option, but finding a balance between the visibility of the watermark and product and still having a well detailed product image is not easy. We may just have to result in a sort of watermark, but something extra wouldn't hurt.