Be sure to read the comments in this article, too. When I last read them, by far the majority of readers showed the same lack of knowledge of copyrights as the infringers in the article, and seemed to have a sense that they're entitled to take anything they find online and use it for free. Wrong!
Attorney sues hundreds over use of Indy skyline photohttp://www.ibj.com/attorney-sues-hundreds-over-use-of-indy-skyline-photo/PARAMS/article/47063
Putting a copyright notice or any other mark on your work hasn't been required by law for decades. Lack of a mark does not mean it's free! At any rate, you can see why more artists and photographers ARE permanently 'marring' their images with giant watermarks. It does deter many infringers, partly because some wrongly believe it's required to mark images. Even so, if an infringer removes the mark, I guess the people in this article think that means it's free. Idiots.