I wonder if there's a market for a rewriting service ... takes a volume of text, and rewrites it using different words so that it's the same content, but not copied.
Such software exists. It's called a spinner. Unfortunately, AFAIK it doesn't actually get around the copyright issues because it's a mechanical translation, not an independent creative work.
interesting, didn't know there was already a little cottage industry here. I'm totally not advocating it, but I'm curious how would anyone know (assuming the spinner actually outputs quality copy)? I guess it would be up to to the prosecution to prove it, or the defense to lie about it, should it come to that.
It's mainly used for various kinds of black hat SEO (comment spam, automatically generating thousand-page websites and so on). From what I've seen, the quality ranges from atrocious (e.g. simply running random words through a thesaurus) to passable, but the goal is just to make the text look reasonably unique to a machine, not to skirt copyright law. If you were given the output and a list of potential source texts, you would not have any trouble figuring out which was the parent.
