http://arstechnica.com/news.ars/post/20070227-8937.html
From the page: “According a patent filing at the US Patent and Trademark Office, Digimarc’s “Method for monitoring internet dissemination of image, video and/or audio files” is a monitoring service that scans the Internet, consuming content as it goes. The system downloads audio, video and images, and then scans them for watermarks. If it finds a watermark it recognizes, the system then contacts that mark’s registered owner and informs them of the discovery.”