Scraping is bad, bad, bad, no matter how you look at it. I don't know why anyone bothers to follow this model. Unless you have a lot of your own unique material dwarfing what you scraped, it's just not something Google likes (nor something I particularly care for). As an original content publisher, it annoys me to no end. Remember this thread about the guy who killed his content farm?
He also killed his news aggregator, built on duplicate content I would assume.