I feel bad for JC Penney who got connect by a shady SEO firm. Google's reaction of completely delisting them sounds like a kill switch action, not an algorithmic tweak to ignore spam. It almost seems like Google just doesn't have the technology to detect and remove spam pages. I'm pretty sure I can do this over a weekend [1]. I wonder if it's because the problem is hard technically, or because Google doesn't have the incentive to do so.

[1] for those who don't remember, this is a tongue in cheek reference to an infamous comment on HN that somebody made claiming he could clone stackoverflow in a weekend.