Last month Yahoo! filed a lawsuit against Facebook that claimed Facebook’s News Feed, ads, and privacy settings infringed on their patents. Today Facebook has filed a countersuit against Yahoo! through 10 of their patents. Facebook said that Yahoo!’s Flickr photostream and their recent activity feature infringes a Facebook patent that is related to generating a personalized feed of stories on a social network. ?While we are asserting patent claims of our own, we do so in response to Yahoo?s short-sighted decision to attack one of its partners and prioritize litigation over innovation,? stated Facebook general counsel Ted Ullyot.