Marcia - 7:35 am on Apr 26, 2008 (gmt 0)
It's not always black hats (competent ones) either. There are scraper sites being sold with "feeds" with a promise to get rich quick.
Google follows the link in from the bloody spammer and gets 403'd straightaway, and our serps are the better for it ... I'll blackhole those scrapes right down to my last knuckle if I have to, and not even give it a second thought.
What's the code for doing that? I've got some pointing to a site from multiple XML "feed" type pages on some domain, found them with Site Explorer.