http://www.digimarc.com/
Digimarc� for Images allows you to embed imperceptible, persistent digital watermarks into your images to communicate ownership and other information � wherever the images travel across the Internet.   According to them, they can run a scan of the Internet and find your photos wherever they appear.  (I was wondering if anyone could still track our images in the free Google program).

This product has been offered with Photoshop for at least 10 years but the first time I looked there was an additional cost and I didn't buy into the idea.

Now, I'm wondering if it is an application that we can use?  I even tried to phone them to ask a few questions but when I asked for the operator it took me to a mailbox (I've got a serious issue with this point and it has already lowered my impression of them).

-If you use this embedded watermark can you submit these photos to agencies?  (Presumably no one can remove.)

It looks like Corbis may already use it:

Many companies and organizations, including Corbis, Microsoft, the Smithsonian Institution, Sony and others rely on Digimarc� for Images to communicate ownership of their content, find where their images are being used online, and provide valuable business intelligence regarding their digital image assets. Now, by adding LicenseStream, you can effectively monetize your images with automated licensing, royalty settlement and renewals.

On page 5 of their best practices guide they state that it works best when images are not comprised of a single flat colour (like a white washing machine against a white wall).  Would this not actually alter the appearance of a photo like a watermark we are accustomed to?

For those of us who have or are thinking about starting their own stock site it may be something worth looking at.  Anyone done any research on these guys?

Here is their PDF "Best Practices Guide"
http://www.digimarc.com/docs/digimarc-for-images-resources/digimarc-for-images-digital-watermarking-best-practices-guide.pdf?sfvrsn=2