Thanks for confirming what I had thought. This community makes a big thing about unauthorized photo use, more than I've seen on photography forums, but there's little that can be done in the real world short of embarrassing the person.
I've sold photos but I've never sold the exclusive rights to my photos. I was paid three times what my normal fee was for a photo that was used in print without my authorization, but it was basically "go away" money before it ever went to court. It was a big organization that didn't want any negative publicity.
As was mentioned in another thread, a water mark will give you credit for the photo. I doubt you'll get much more from the average person with a website.
If anyone has actually sued and won, I'd love to hear about it.