Watermarks or no watermarks, it's also a rather fault-proof method to protect your works. Ugly as they are but they always work. You only make it easier for art thieves to steal your works without watermarks.
Watermarking may not, either. And it's a real pain looking past watermarks to see the art, meaning even non-thieves have to look at a cruddy watermark distraction. Though, I even use them, depending on the situation. I just don't like them, I guess.
Looks like they're at it again I filed a report with ebay if that helps at all. Man that guys site had rips from everywhere! It's a shame though, gotta love exposure, but at what price! Suing is tedious and time consuming, but if everyone here sends at least one email to the seller about what he did we should be able to flood his inbox with enough crap to send a message (send several if you have the time its life little aggravations that'll get ya)
First of all contact the Da help desk (back yourself up with a formal complaint that the person indeed stole your art ) . Then E bay ( give them a link to your original art, pointing out the date when it was made and that it belongs to you yadayadayada) And finally the seller - but it will probably be in vain, they tend to be verry ... how shall i put this in a nice and clean way ... intellect challenged : ))
If he refuses to take it down, remind him that unless the art in question is 30 pixels or less of a quality, compared to the original, then its considered theft, and the system is on your site MUhahahah XD