I was just a victim of copyright thievery.
I bid for a job on Craigslist for a cigar shop and the owner wanted a "mock-up" before hiring a designer to make their website. Well, that should have been my first clue that the guy wasn't a honest person because normally, a designers work should stand for itself and someone should hire you based on that work. But I was hoping to get the job and hoped he was honest. So, after several hours of hard effort to make a great layout, I submitted to the owner for review. No word back... nada, nothing. So I figured he'd went with someone else, oh well, right?
A few months later, I looked up the shop to see what design beat me out, and low and behold, there was an almost dead-on look-a-like of my design staring back at me from his site. I was pissed! (and flattered because I DID HAVE THE BEST DESIGN). Anyway, I proceeded to confront the owner telling him he had no right to use my design concept without my permission and if he didn't pay me, I'd go to his ISP. He said he'd received many designs that looked like the one I submitted, and went with another designer (Yeah right). So, I did what I threatened to do. A design is like a signature. We all use the same letters, but they look very different from one another.
I'm happy to say, Yahoo agreed with me, and took down the site. It felt very good to have justice served and now he's going to be getting a letter from my lawyer! I will be paid for my hard effort.
If someone takes your work and claims it as their own, and you can prove it. You can take it to their Internet Service Provider (which can be found from their domain registration on WHO IS) and complain through the proper channels.