The patent-infringement lawsuit battle has intensified, with Amazon hitting back at Discovery Communications in vengeance! After Discovery sued Amazon for patent infringement pertaining to its e-book reader, Kindle, in March, Amazon has countersued Discovery for infringing on its patents related to several e-commerce aspects.

In its suit filed on May 15 in federal court in Seattle, Amazon - along with denying infringing on Discovery patents related to Kindle on the argument that the art pre-existed - said that Discovery has infringed on Amazon's intellectual property (IP) covering an "Internet-based customer referral system" in its online store.

Amazon alleges that Discovery's online store infringes four of Amazon's patents associated with ways users refine searches for products or get recommendations based on earlier purchases. The countersuit by Amazon, wherein it has sought a court order regarding a block use of its inventions and cash compensation, apparently is its calculated move to initiate some kind of a negotiation with Discovery!

Saying the Discovery patent was neither valid nor infringed, the Seattle-based Internet retailer added that Discovery had not only withheld information, but had also misled the US Patent and Trademark Office for obtaining the patent in question.

However, in reaction, Discovery spokeswoman Michelle Russo said: "Discovery remains committed to protecting its intellectual property assets and we have continued confidence in the merits of our case."