http://ywyfg67txaji5y24k5ieexsecr4ocnsgr6uogv5b73kqgzgjb4vskkyd.onion/2013/08/index.html
Their motivation was clearly Tormails database, which contains thousands of email conversations between for example users of the Silk Road Marketplace, or more importantly maybe even communication between whistleblowers and journalists. Since the Hidden Wiki and OPVA, 2 of the largest remaining hidden services, are also down since yesterday, we suspect the FBI / NSA operation is still ongoing.