Unfortunately, I can go to Flickr and look at all the resized versions of any of my photos and the EXIF data is stripped from each and every one of them, meaning that even though I have a version out there with my copyright embedded in the EXIF data, there are a handful of copies, produced whenever anything is uploaded to Flickr, that have that EXIF data stripped. So if you're willing to work with a "Large" file instead of my original, then technically there are 5-15 "orphan works" ON flickr for every well documented and copyrighted version of my photos. That's been a concern of mine for a while, and this has me ready to yank everything off of there.
What really gets me is that these same large companies will sue the pants off of anyone who dares borrow even a second of a song or an smidgen of an idea from a work that they own, even though the thing they based it on was "borrowed" from public domain or a previously expired copyrighted work (cough, cough, Disney, cough).