Just thought I'd offer up an example of not fair use. Check out this article:
And then this one:
You'll notice that the second is credited to Maria Sudekum, Associated Press. And the first one...is credited to no one. Wanna take a bet on which one is the unauthorized copy?
It just goes to show that there is real value in provenance. There is value in content beyond what someone will pay for or what you can get for ads on it. Who is going to trust a site that plagiarizes people? No one.