Hmm. Yeah, the guy has one of mine up as well, though at least he doesn't offer it for sale. A bit sneaky/not sneaky about the whole thing, as he cropped it just above where I placed my watermark thus cutting that out, but then below in the text he shows it as "(c) Scott Turner". Go figure.
I don't mind when someone shares a photo I've made available publicly given a) it's not modified, b) it's obviously credited, and c) there's no attempt to use it commercially. I guess I should be happy with ~1.5 out of 3, eh?
Scott