The director of the National Security Agency (NSA) has said that with Anonymous' attacks increasing in frequency and effectiveness, the United States power grid could be under threat.
This assessment came as part of meetings between the NSA head and the White House - according to Wall Street Journal sources - where it was warned that web based attacks were an emerging threat to US infrastructure. That isn't a level that Anonymous has hit out at yet, but it has gone from embarrassing companies, to quite publicly slapping the face of major government organisations.
Confidence, if anything, is growing. Whether that will lead to serious interruptions of necessary resources for the general populace remains to be seen. It seems likely from the claims made by the Anonymous and Antisec movements, that the main focus is removing corporations from the internet and pointing out poor security when dealing with end user data. Keeping it to the online world allows the hacktivists to control the field of battle - to use a little metaphorical terminology so well loved by those involved.
Anonymous has almost always attempted to garner a Robin Hood like image from the general public. It's supposed to be defending individual freedom and internet based rights. Shutting down a power grid and denying average people from electricity is unlikely to do that - especially since government organisations and corporations would likely have backup alternatives during the blackout.
However, there is of course the arm of Anonymous that is anarchic. This is less common these days and much more of an original aim of the movement. More recently it's been far more focused - with specific targets of SOPA, PIPA and ACTA being a strong reason for attacks.
Even if Anonymous did decide to take a swing at attacking the power grid, officials claim that it's not something they're unfamiliar with. Apparently the systems face regular attacks - though they don't sound overly confident in the published quote: "The industry is engaged and stepping up widely to respond to emerging cyber threats. There is a recognition that there are groups out there like Anonymous, and we are concerned, as are other sectors."
Not everyone is as worried though, with Anonymous at least. Some believe while the anons may yet attempt something as audacious as attacking a government infrastructure, it is still years away of being capable of doing so.
One hypothesised situation is that an overseas government could develop a technique and then outsource it to a movement like Anonymous. While this might read fine on paper, in practice it seems very, very unlikely that any government would be able to have an open dialogue with Anonymous - that wasn't filled with memes - resulting in cooperation.
Claims of power grid outages sound more like something out of a movie than real world options for hacktivists. Even it was a reality though Bruce Willis and Justin Long could probably save us anyway so I'm not too worried.