Now it’s Amazon’s turn: the online retailer is suing Discovery (NSDQ: DISAB) Communications (NSDQ: DISCA) over four patents related to e-commerce, TechFlash reported (via WSJ). Amazon’s suit, which was filed in U.S. District Court in Western Washington on Friday, specifically concerns patents for search and recommendation. In March, Discovery initiated legal action against Amazon (NSDQ: AMZN) over e-commerce patents. In particular, that initial suit alleged that Amazon’s sale of the Kindle and its electronic book delivery infringes on one of the patents owned by Discovery and its founder John S. Hendricks on a digital content and delivery system that was filed in the 1990s, but wasn’t issued until Nov. 20, 2007. The Discovery suit was filed in a U.S. District Court in Delware.

SEE ALSO: Updated: Discovery Sues Amazon For Patent Infringement Over Kindle E-Book Delivery

Amazon did not specify what damages or penalties it is seeking against the cable TV operator. In its suit, Discovery did not seek to halt sales of the Kindle, and so is likely expecting to get a cut of its sales, assuming Amazon is able to build on the enormous momentum generated around the e-reader so far.