An article in the Financial Times has stated that hacker group Anonymous is behind the PlayStation Network being down. The article pins blame on the PSN break-in on "an individual or handful of supporters of" Anonymous' OpSony, Anonymous' since called-off response to the lawsuit between Sony and hacker Geohot. In response to the article, Anonymous has issued a press release that questions the accuracy of FT.com.
According to the Financial Times' source, technical details on breaking into Sony's networks were floating around Anonymous chat rooms shortly prior to the attack, and “the hacker that did this was supporting OpSony’s movements." .
While Anonymous (or at someone claiming to speak for Anonymous) issued a press release questioning the accuracy of the FT.com story, the post contains what looks like a threat or warning:
"Outraged about the blatant coverup and shameful misdeeds, other internet hacker groups will apparently proceed with attacks  over Sony's mishandling of the matter. These reactions prove that requesting legislation to cover up corporate crimes and the abuse of law is frowned upon by all online communities, not just the Legion of Anonymous. Apparently Sony will have to learn the hard way that corporate malfeasance will not go unpunished. When the dust settles Sony may have more to fear from a massive class action lawsuit by their user base than the brief actions of the Global Hacker Nerd Brigade, Anonymous... Let THE GAMEs begin. :>"
The problem with talking about the involvement of Anonymous with anything, of course, is that their membership is entirely anonymous, so anyone can claim to be part of their group, and anything can be blamed on them. Hypothetically, if a guy who hangs around Anonymous chat rooms gleans some technical information that allows him to work his way into Sony's network and boost a bunch of credit card numbers, does this mean Anonymousis responsible for the crime? If you were a criminal interested in stealing personal data from a network in order to sell it, wouldn't it make sense that to hang around internet forums where exploiting security holes is discussed?
As the FT.com's hacker source puts it: “If you say you are Anonymous, and do something as Anonymous, then Anonymous did it... Just because the rest of Anonymous might not agree with it, doesn’t mean Anonymous didn’t do it.”
Source: Financial Times