One of the biggest names on the Internet has rescinded their support of a controversial computer bill. Social media giant Facebook says they are no longer favoring the Cyber Intelligence Sharing and Protection Act, or CISPA.

From Silicon Valley to Washington, DC, all eyes were on CISPA last year when Rep. Mike Rogers (R-Mich.) and Sen. Dutch Ruppersberger (D-Calif.) touted the bill across the United States as a much-needed solution to the sky-rocketing number of cyberattacks waged at American computer networks. CISPA, said its supporters, would prevent those hazardous hacks from ravaging the country’s cybergrid by asking private sector Internet businesses to share threat information with the US government.

When CISPA went before Congress last year, the bill passed in the US Senate after garnering the support from Silicon Valley heavyweights like Microsoft and Facebook. Before the bill could make it to the House, though, a number of proponents withdrew their enthusiasm in the wake of a massive grassroots Internet campaign. CISPA ultimately never made it to the House, but last month the co-authors of the original bill re-introduced the act before Congress. The odds of CISPA seeing serious support like it did last year is now up in the air, however, after Facebook acknowledged this week that it will no longer back the bill.

CNet reporter Declan McCullagh writes on Thursday that Facebook’s name has suddenly disappeared from a list of CISPA supporters. While Facebook VP Joel Kaplan wrote Rep. Rogers last February to "to commend you on your legislation," the website’s stance has changed drastically during just the last 13 months. When McCullagh reached out to the social networking site for comment, a spokesperson for the site confirmed that one of the biggest entities on the Internet is not on-board with the bill this time around.

Facebook, says McCullagh, has rescinded their support of the bill because the website prefers a legislative "balance" that ensures "the privacy of our users.”

“We are encouraged by the continued attention of Congress to this important issue and we look forward to working with both the House and the Senate to find a legislative balance that promotes government sharing of cyber threat information with the private sector while also ensuring the privacy of our users,” a spokesperson for the site tells CNet.

Facebook’s falling-out comes nearly a year after Microsoft eventually walked away from the bill on their own, and could come as a serious thorn in the side of Rep. Rogers and Sen. Ruppersberger, who would benefit heavily from the website’s approval. Commenting to CNet, Microsoft's vice president for trustworthy computing said that his company is indeed still opposed to the legislation and is unlikely to do another about-face.

"Microsoft believes that any proposed legislation should facilitate the voluntary sharing of cyber threat information in a manner that allows us to honor the privacy and security promises we make to our customers,” MS’s Scott Charney tells McCullagh.

Privacy concerns have been the driving force in anti-CISPA actions, primiarly since the bill would alleviate cooperating private businesses from any liability once they let the government sift through personal data. "CISPA would allow ISPs, social networking sites and anyone else handling Internet communications to monitor users and pass information to the government without any judicial oversight," EFF Activism Director Rainey Reitman said in a statement last year. "The language of this bill is dangerously vague, so that personal online activity -- from the mundane to the intimate -- could be implicated."

Just weeks after CISPA 2.0 was unveiled, a petition asking the White House to stop the bill has already received over 100,000 signatures. Having surpassed that threshold, the Obama administration will now have to respond in the coming weeks. Given the White House’s insistence on surpassing some sort of cyber law, though, a guaranteed veto is almost uncertainly out of the question: Speaking to ABC News earlier this week, Pres. Obama urged Congress again to consider the bill, saying, "There are ways that we can harden our critical infrastructure, our financial sector," and that Congress "need[s] to get this done."