Facebook on Tuesday fired back at Yahoo! with a countersuit charging that the floundering Internet pioneer is violating the social network\'s patents and not the other way around. The move came after Yahoo! filed suit against Facebook in a California court last month accusing the social networking giant of infringing on 10 patents. \"From the outset, we said we would defend ourselves vigorously against Yahoo!\'s lawsuit, and today we filed our answer as well as counter-claims against Yahoo! for infringing 10 of Facebook\'s patents,\" said Facebook general counsel Ted Ullyot. \"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.\"