More on the FatWallet DMCA takedown here via Chilling Effects and via Copyfight.  One point I haven’t seen is the possibility that an unreleased circular is protectable as confidential information.  Also, one red herring in the blawg world is the cards case.  An expert (such as a collector) estimating what the prices of collectables are in an illiquid market can be said to be exercising expertise in a way that Walmart pricing socks is not.  So I don’t see price guide cases as controlling here.