I think Copyscape is an amazing site and a concept that is revolutionizing the way people write for the web. Instead of clients worrying that something they are buying might be stolen, either whole or in part, they can check it quickly via Copyscape. Try to wrap your mind round it- it checks billions of websites and lets you know where in the world anything you have ever written can be found duplicated.
I love that clients can use it to make sure my items are original. The miracle of Copyscape means that clients will know immediately if anything was copied. It gives clients confidence and lets writers know if their work has been stolen.
Case in point: here is an article that I wrote for How to Do Things: http://www.howtodothings.com/hobbies/a4439-how-to-write-an-editorial.html
Here it is reproduced by someone else who put their name on it: http://climatechallenge.org/wiki-sources/media-guide/op-eds
If you will notice, the thief is far from crafty- the date that I wrote it and the date that he stole it are clearly visible. I wrote it three months before he says he did. Not too smart. Why do people even do this? Surely they are aware of the miracle that is Copyscape. And if they aren't, they are about to find out.