Hacker cabal, Anonymous, who many suspected were behind the PSN outage controversy that has been raging since April the 21st, have long denied involvement with the issue, despite threatening Sony with such an attack. However, while Sony has admitted an outside party was responsible for the crash, they, too, have ruled out Anonymous.
Speaking at their conference, Kaz Hirai told a reporter "Anonymous has not been implicated in any way with the current attacks". I'm actually astounded we - or seemingly Sony themselves - have no idea who's responsible for the outage. They've even enlisted the help of the FBI and Department of Homeland Security to identify the culprit(s). Brendan has more for you on Sony's conference and the PSN situation right here.