Opposition to pending cyber-security legislation ramped up today when several high-profile Internet groups joined forces to protest the Cyber Intelligence Sharing and Protection Act of 2011 (CISPA).

Opposition to pending cyber-security legislation ramped up today when several high-profile Internet groups joined forces to protest the Cyber Intelligence Sharing and Protection Act of 2011 (CISPA).

A coalition of Internet advocacy groups - including the American Civil Liberties Union (ACLU), the Electronic Frontier Foundation (EFF), and Reporters Without Borders - launched "a week of Internet-wide protests" today, which calls on Web users to tweet their lawmakers with their opposition to the bill.

The effort is using the #CISPA and #CongressTMI hashtags on Twitter, and planning letters and articles of opposition that will outline what they consider to be the civil liberty implications of the legislation.

"Freedom of expression and the protection of online privacy are increasingly under threat in democratic countries, where a series of bills and draft laws is sacrificing them in the interests of national security or copyright," Reporters Without Borders said in a statement.

Sponsors and supporters of CISPA claim the bill is intended to allow private companies and the government to communicate in the event of a cyber threat. Detractors, however, argue that it will simply make it easier for the feds to get their hands on users' personal information.

The effort comes several days after . Joel Kaplan, vice president of U.S. public policy at Facebook, argued that the bill will help guard the social network against cyber attacks via information sharing and denied that any user information will be shared with the government.

In a Sunday blog post, Rainey Reitman, the EFF's activism director, argued that CISPA is unnecessary.

"This stated goal of Facebooknamely, for companies to receive data about cybersecurity threats from the governmentdoes not necessitate any of the CISPA provisions that allow companies to routinely monitor private communications and share personal user data gleaned from those communications with the government," Reitman wrote.

CISPA has drawn comparisons to the Stop Online Piracy Act (SOPA) and the PROTECT IP Act (PIPA). Those bills would have allowed the Justice Department to go after international, "rogue" websites that trafficked in counterfeit goods, but it prompted concern about the impact on legitimate businesses. Facebook, which opposed SOPA and PIPA, as well as the sponsors of CISPA, have denied any similarities between the bills.

"#CISPA differs markedly from SOPA in both its goals and its actual language," bill sponsor Rep. Mike Rogers tweeted today, pointing to a Talking Points Memo article.

Co-sponsor Dutch Ruppersberger today also re-tweeted messages from the House Intelligence Committee, which insisted that "Nothing in #CISPA provides any authorities requiring companies to take content off the Internet or to stop access to websites."

"If govt violates use limitations in info shared, #CISPA allows for govt liability for actual damages, costs, & atty's fees in a fed lawsuit," reads another message.

A copy of the bill is available on the committee website, as is a Q&A about the legislation. It was approved by the panel in December by a vote of 17 to 1, but has not yet been considered by the full House or Senate.

Other groups participating in this week's protest include Access Now, American Library Association, Avaaz, Canadian Internet Policy and Public Interest Clinic, Center for Democracy and Technology, The Constitution Project, Demand Progress, Fight for the Future, Free Press, OpenMedia.ca, Open the Government, Privacy Rights Clearinghouse, Reverse Robo Call, Sunlight Foundation, Techdirt, and TechFreedom.