A number of private companies and trade associations have expressed support for CISPA. Many of them sent letters of support to the U.S. House of Representatives for either H.R. 3423, H.R. 624 or both, including AT&T, Verizon, US Telecom, Comcast, Time Warner Cable, the National Cable & Telecommunications Association, Edison Electric Institute, Financial Joint Trades, Financial Services Roundtable, Boeing, Lockheed Martin, IBM, Intel, Oracle, Symantec, Microsoft, Facebook, TechAmerica, the Internet Security Alliance, Juniper Networks, the National Cable & Telecommunications Association and the Chamber of Commerce. Facebook and Microsoft both backed away a little after protests and stated or implied that they would support changes to the final legislation that addressed privacy concerns.
The letters of support include praise for breaking down existing barriers to the timely sharing of cyberthreat intelligence with private entities, not placing regulatory burdens on private companies and protecting them from frivolous lawsuits and legal uncertainty with regards to sharing information, among other things.
But some companies and organizations concerned with privacy and civil liberties have vigorously spoken out against CISPA, including the Electronic Frontier Foundation, the American Civil Liberties Union, Access Now, the American Library Association, the Society of American Archivists, the Cato Institute, the Center for Democracy and Technology, the Entertainment Consumers Association, the Sunlight Foundation, Reporters Without Borders, the Society of Professional Journalists, the Rutherford Institute, the Republican Liberty Caucus, Mozilla and Tech Freedom, among others. Notable individuals who have expressed concerns include former Representative and Presidential candidate Ron Paul, who called the bill "Big Brother writ large," and Tim Berners-Lee, the inventor of the World Wide Web. And of course, there was the President's veto threat.
The EFF and some other opposing groups organized a "Week of Action" in mid-April 2012 to protest CISPA, during which they waged a grassroots campaign asking people to sign petitions, write, call and tweet Congressmen and otherwise express opposition to the bill. Nearly a million people did so the first go round, but despite this activity, CISPA did pass in the House -- albeit with a few changes.
As of early spring of 2013, similar pushes are being made to protest the bill anew. Within a day or so of CISPA being reintroduced in the House, hundreds of thousands of online signatures were reportedly collected and delivered to the U.S. House Intelligence Committee. We likely haven't heard the end of vigorous arguments on both sides of the issue.