There a number of solutions, though most are cost prohibitive (+$100k). At PornGuardian.com, we are working on a watermarking system that is a lot less expensive. It help you identify who is uploading your content. It's in beta testing now, and we have already caught two pirates.

We also have a community outreach program, and through it have shut down (or at least disabled) two big blogs. As we grow will be fleecing more and more blogs of all their content. (Read our latest press release at our site (PornGuardian dot com).

Best,
Dominic