Will members of the hacker group Anonymous try to bring down Facebook?

Some members of Anonymous, the nebulous group of hackers whose high-tech activism has wreaked havoc on law enforcement agencies, government ministries and corporations, appear to have a new target in their cross-hairs: Facebook.

A threatening message on YouTube was allegedly disseminated by affiliates of the shadowy collective, which in recent days has hijacked the websites of the Syrian Defense Ministry (in protest of the restive nation's autocratic regime) and dozens of rural police offices in the United States (in retaliation for the recent arrests of some of the group's suspected cohorts). "If you're a willing activist or guy who just wants to protect the freedom of information then join the cause and kill Facebook for the sake of your own privacy," implores the narrator of the message, using a voice scrambler.

Facebook chief executive Mark Zuckerberg has repeatedly been criticized for his alleged lack of concern for the privacy of his 700 million users.

"Facebook has been selling information to government agencies and giving clandestine access to information security firms so they can spy on people all around the world," the Anonymous message, titled "Operation Facebook," claims. (It was uploaded on July 16, but it only began circulating widely around the web on Tuesday. You can listen to it above.)

"Everything you do on Facebook stays on Facebook regardless of your privacy settings, and deleting your account is impossible," the statement continues. "Even if you delete your account, all of your personal info stays on Facebook and can be recovered at any time. Changing the privacy settings to make your account more private is also a delusion. Facebook knows more about you than your family. ... You are not safe from them nor from any government. One day you will look back on this and realize what we have done here is right. Think for awhile and prepare for a day that will go down in history: Nov. 5, 2011."

If successfully carried out, the allegedly pending attack would coincide with Guy Fawkes Day, a British celebration that commemorates a failed assassination attempt on King James I of England in 1605. Members of Anonymous are known to don masks resembling Fawkes.

A spokesman for Facebook declined to comment. But Anonymous weighed in on its Twitter account. The group initially claimed the YouTube video was a hoax, but later clarified: "#OpFacebook is being organised by some Anons. This does not necessarily mean that all of #Anonymous agrees with it." A subsequent tweet reads: "We prefer to face the real power and not to face to the same medias that we use as tools."

Some observers are skeptical about the authenticity of the threat.

"Why didn't this news spread like wildfire three weeks ago?" writes Emil Protalinski on ZDNet. "Whenever Anonymous or [affiliated hacker group] LulzSec declare a new target, the world definitely notices. Furthermore, while Guy Fawkes Day is a perfectly understandable choice, it's very far away. There are 112 days between July 16, 2011 and November 5, 2011: Anonymous rarely gives more than a few days notice, if at all."