Originally Posted by AVC

Google has been ranking some scraper sites also, but it is up to webmasters to help out and report spam sites as such when they see folks stealing content and ranking for it.

Even with all the great technology Google possesses, when they change the algo's bad things can happen, good sites drop and bad sites can rank, but if you report scammers when you see them, they have no chance to rank if their sites are de-indexed and that is what I do when I see a content scraper site ranking.

If you think a site is keyword stuffing, report it, but try not to report stuff just because you are mad that they are ranking ahead of you, make sure you have a crook or con man to report or Google will disregard your future spam or paid link reports.