Someone ratted out Overstock just like JC Penny a couple weeks ago. They got a big ol' G slap.
Google Penalizes Overstock for Search Tactics - WSJ.com
Looks like they were getting anchor text EDU links which is why we've been seeing them in the top 5 for everything lately. Not anymore...
Just goes to show that we're all screwed in our attempts to get to the top spots for the niches we're targeting.