U.S. Markets closed

Facebook countersues Yahoo

The top social networking website is making good on a promise to vigorously defend itself from a patent-infringement lawsuit that Yahoo (NASDAQ:YHOO - News) filed in March. Facebook (NASDAQ:FB - News) on Tuesday filed a countersuit. While Yahoo's legal offensive claimed Facebook infringed on 10 Yahoo patents, including ones for online advertising, the countersuit accuses Yahoo of infringing on 10 Facebook patents related to generating a personalized feed of stories on a social network, Reuters said.