Reaction to the Stop Online Piracy Act (H.R. 3261) - as well as its Senate counterpart, the PROTECT IP Act (S. 968) - has been severe. Here are some of the highlights from the growing chorus of opposition – in Letters to Congress, In the Press, in Blog Posts and Statements, and in Long-form Analysis
Here is a list of organizations and individuals  expressing concern with SOPA and PROTECT IP.
Sandia National Laboratories: Letter regarding SOPA and PROTECT IP 
[We have reviewed the bills] and believe that the DNS filtering/redirection mandates . . . 1) are unlikely to be effective, 2) would negatively impact U.S. and global cybersecurity and Internet functionality, and 3) would delay the full adoption of DNSSEC and its security improvements over DNS.
83 Internet Inventors and Engineers: Letter regarding SOPA and PROTECT IP 
If enacted, either of these bills will create an environment of tremendous fear and uncertainty for technological innovation, and seriously harm the credibility of the United States in its role as a steward of key Internet infrastructure.
Nine Major Internet Companies: Letter regarding SOPA and PROTECT IP 
We are concerned that these measures pose a serious risk to our industry’s continued track record of innovation and job-creation, as well as to our Nation’s cybersecurity.
17 Prominent Internet Company Founders: Letter regarding SOPA and PROTECT IP 
[SOPA and PIPA threaten to] require web services, like the ones we helped found, to monitor what users link to, or upload. This would have a chilling effect on innovation.
Hundreds of CEOs, Founders, Entrepreneurs, and Independent Businesspeople: Letter regarding SOPA 
Under SOPA, the process required to respond to litigation or a complaint would likely absorb an average small host’s entire yearly profit. Given the small business nature of the hosting industry, hosting businesses are not in a position to absorb the litigation costs associated with SOPA.
Laurence H. Tribe, Professor of Constitutional Law at Harvard: Letter regarding SOPA 
The notice-and-termination procedure of Section 103(a) runs afoul of the 'prior restraint' doctrine, because it delegates to a private party the power to suppress speech without prior notice and a judicial hearing.
110 Law Professors: Letter regarding SOPA 
In sum, SOPA is a dangerous bill. It threatens the most vibrant sector of our economy – Internet commerce. It is directly at odds with the United States’ foreign policy of Internet openness, a fact that repressive regimes will seize upon to justify their censorship of the Internet. And it violates the First Amendment.
13 Advocacy and Nonprofit Organizations: Letter regarding SOPA 
As drafted, SOPA radically alters digital copyright policy in ways that will be detrimental to online expression, innovation, and security.
41 International Human-Rights Groups: Letter regarding SOPA 
By instituting this practice in the United States, SOPA sends an unequivocal message to other nations that it is acceptable to censor speech on the global Internet.
American Society of News Editors: Letter regardubng SOPA 
It is our longstanding dedication to First Amendment rights that drives our opposition to SOPA. Navigating the balance between copyright and free speech demands precision, and in seeking to protect the interests of copyright holders, the First Amendment requires Congress to adopt the least restrictive intrusion on speech available.
Global Network Initiative: Letter regarding SOPA 
The Global Network Initiative (GNI) is concerned that provisions of the proposed U.S. law H.R. 3261, the Stop Online Piracy Act (SOPA) and related legislation could have dangerous unintended consequences for freedom of expression and economic innovation in the U.S. and around the world.
CCIA, NetCoalition, and CEA: Letter regarding SOPA 
Under this bill, a foreign or domestic Internet site that has broken no U.S. law can nevertheless have its economic lifeblood cut off upon a single [allegation] from a copyright or trademark owner.
Library Copyright Alliance: Letter regarding SOPA 
Two provisions of section 201—the definition of willfulness in section 201(c) and the expansion of criminal penalties to public performances in section 201(a)—are troubling. While each provision is problematic in its own right, the two together could threaten important library and educational activities.
104 Educators: Letter regarding SOPA and PROTECT IP 
Online services providing innovative educational content or services require the legal certainty and protections defined in the DMCA. The proposed legislation would undermine legal certainty and in turn chill the creation of innovative learning opportunities.
U.S. Consumer-Rights Groups: Letter regarding SOPA 
We are concerned that some of the measures proposed by this bill and the breadth of its scope could make it more likely to harm consumers’ interests. In particular, we are worried the bill could close off online exchanges that provide lower prices for consumers; reduce online security; and allow for anti-consumer practices by online service providers.
Institute for Intellectual Property & Social Justice: Letter regarding SOPA 
Certain of the Act’s provisions would have a dire impact on the socio-economic interests and civil rights of members of various marginalized communities and other underserved intellectual property stakeholders.
Vint Cerf, One of the "Fathers of the Internet": Letter regarding SOPA 
Unfortunately, the amendments to SOPA do not resolve the fundamental flaws in this legislation; the bill will still undermine cybersecurity including the robust implementation of DNS Security Extensions, known more commonly as DNSSEC.
Rey Ramsey, CEO, TechNet: Letter regarding SOPA 
Although H.R. 3261 takes aim at the problem of online piracy, its regulatory approach does so in such a way that could threaten many features that make the internet function well and which allow users to access, create, share, and pay for online content.
David Ulevitch, CEO, OpenDNS: Letter regarding SOPA and PROTECT IP 
If passed, they will be devastating to the growth of the Internet economy in the United States, will take jobs overseas and will have a chilling effect on innovation.
Andrew Lee, CEO, ESET North America: Letter regarding SOPA and PROTECT IP 
This legislation, if passed as currently written, would have a chilling effect on the economy of the United States.
Haroon Mokhtarzada, CEO, Webs, Inc.: Letter regarding SOPA 
Our business model is built on making it extremely easy for small businesses and individuals to affordably create, edit, and manage websites […] SOPA would radically change the landscape and make offering a service like ours impossible, squelching a valuable service and vehicle for free speech.
Adam Huttler, Executive Director, Fractured Atlas: Letter regarding PROTECT IP 
As a national non-profit that supports artists and arts organizations, we write to you today with concerns regarding legislation currently being considered to deal with websites and services that traffic in the unauthorized distribution of American intellectual property, including copyright. Fractured Atlasr epresents over 20,000 organizations and individuals from a diverse background that includes performers, filmmakers, musicians, composers, writers and more. We are compelled to weigh in because too often, trade groups representing powerful entertainment conglomerates are seen as speaking for all creators on such crucial issues.
Larry Downes, CNET: SOPA: Hollywood's latest effort to turn back time 
House leaders assured Silicon Valley they would correct serious defects in the Senate bill. Unfortunately, SOPA does just the opposite. . . . If passed, the bill would give media companies unprecedented new powers to shape the structure and content of the Internet.
Editorial, The New York Times: Going After the Pirates 
Online piracy is the bane of the Internet. Still, bills proposed in the House and the Senate have overreached. The legislation needs to be tightened to protect intellectual property without hindering online speech and innovation.
Editorial, Los Angeles Times: Piracy vs. an open Internet 
The potential result [of SOPA] is that fewer companies would try to create the next YouTube . . . And there would probably be a chilling effect on speech as sites block some fair uses of copyrighted content just to avoid ending up in court.
Editorial, San Jose Mercury News: Congress should kill online piracy bill 
There are times when Silicon Valley really can help you understand the complexities of legislation that will affect the tech industry - and the world economy. The raging debate over the proposed Stop Online Piracy Act is one of those times. . . . It's not just the future of the industry that's at stake here. It's national security.
Rebecca MacKinnon, The New York Times: Stop the Great Firewall of America 
Congress, under pressure to take action against the theft of intellectual property, is considering misguided legislation that would strengthen China’s Great Firewall and even bring major features of it to America.
David Carr, The New York Times: The Danger of an Attack on Piracy Online 
Virtually every traditional media company in the United States loudly and enthusiastically supports SOPA, but that doesn’t mean it’s good for the rest of us. The open consumer Web has been a motor of American innovation and the attempt to curtail some of its excesses could throw sand in the works of a big machine on which we have all come to rely.
L. Gordon Crovitz, Wall Street Journal: Horror Show: Hollywood vs. Silicon Valley 
These bills would go so far to protect copyright that they would strangle the Internet with regulation. The Web would be transformed from a permissive technology where innovation is welcome to one where websites are shut down first, questions asked later.
John Healy, Los Angeles Times: A bipartisan attempt to regulate the internet 
[SOPA pushes stakeholders] even further apart. . . . There's consensus to be had on combating the likes of The Pirate Bay, but it's not to be found in HR 3261.
Michael Hiltzik, Los Angeles Times: Big guns take aim at Web piracy 
As Internet advocates and leading online companies have been pointing out, the measures have fatal shortcomings. They're so sloppily drafted that they would expose not merely "rogues" but largely innocent websites such as YouTube and Facebook — any site, in fact, that allows users to post content online themselves — to heavy-handed enforcement by government and private entities alike.
John Naughton, The Observer: Sopa and Pipa: don't let big business break the internet 
The most worrying aspect of these bills is that they would distort the architecture of the internet in ways that would cripple its capacity for enabling innovation – something that has been eloquently pointed out to senators and congressmen by many of the network's original architects.
David Sohn and Andrew McDiarmid, The Atlantic: Dangerous Bill Would Threaten Legitimate Websites 
Congress is considering sweeping Internet legislation that purports to target "rogue websites" with the intent of cracking down on the theft of everything from movies to songs to designer handbags. While the goal is laudable, too many innocent websites would wind up in the crosshairs. These bills (the PROTECT IP Act in the Senate and the Stop Online Piracy Act, or SOPA, in the House) would do more harm than good to cybersecurity, the Internet economy, and online free expression.
Steve Blank, The Atlantic: SOPA Is a Symbol of the Movie Industry's Failure to Innovate 
The SOPA bill (and DNS blocking) is what happens when someone with the title of anti-piracy or copyright lawyer has greater clout than your head of new technology.
Neil Stevens, The Daily Caller: SOPA is a threat to American Internet leadership 
The Stop Online Privacy Act (SOPA) — a bill currently before the House Judiciary Committee — is a threat to America’s ability to lead the Internet, and must be defeated before it has a chance to damage America’s ability to generate jobs and economic growth online.
Julian Sanchez, New York Post: Killing the Internet to Save Hollywood 
SOPA wouldn’t just be costly and futile: It would deter innovation, interfere with legal speech protected by the First Amendment and (as the geeks at Sandia put it) 'negatively impact US and global cybersecurity and Internet functionality.'
Ivan Sigal and Rebecca MacKinnon, CNN: Online piracy laws must preserve Web freedom 
'In China "copyright" is one of many excuses to crack down on political movements,' a Chinese blogger, Isaac Mao, told us. 'If a new law like SOPA is introduced in the U.S., the Chinese government and official media will use it to support their version of "anti-piracy."'
The Economist: Rights and wronged 
[SOPA] would rope intermediaries into law enforcement to an unprecedented degree, and give rights-holders exceptional power.
Alex Howard, O'Reilly Radar: Congress considers anti-piracy bills that could cripple Internet industries 
The bottom line here is that, as currently drafted, SOPA and the PROTECT IP Act have the potential to negatively affect innovation and Internet security, and enshrine into law the principle that a website hosting user-generated content is liable for any infringing content posted to it.
James Temple, San Francisco Chronicle: Stop Online Piracy Act would stop online innovation 
It would chip away at critical safeguards that have shaped the Internet as we know it today, and many worry it would make it far more difficult for the next YouTube, Facebook or Craigslist to emerge and succeed.
Chris Bronk, Houston Chronicle: The wrong way to stop online piracy 
The powers proposed in SOPA and PROTECT IP do not secure the Internet or protect the overwhelming number of U.S. companies, from tech startups to law firms, with IP concerns. Yes, Congress needs to think about how government and industry must cooperate on protecting IP, but it needs to do so in a manner that accepts technological reality and embraces the innovative, entrepreneurial nature of the Internet ecosystem.
Nancy Scola, Salon: Congress seeks to tame the Internet 
SOPA targets search engines, Internet service providers, ad networks and payment networks precisely because those components are so central to the functioning of the Internet. Those are digital forces that should be messed with only with the greatest of care.
Michael Geist, Toronto Star: Internet belongs to us, U.S. argues 
The U.S. approach is breathtakingly broad, effectively treating millions of websites and IP addresses as 'domestic' for U.S. law purposes.
Mark Lemley, David S. Levine, and David G. Post, Stanford Law Review: Don't Break the Internet 
[PROTECT IP and SOPA] share an underlying approach and an enforcement philosophy that pose grave constitutional problems and that could have potentially disastrous consequences for the stability and security of the Internet’s addressing system, for the principle of interconnectivity that has helped drive the Internet’s extraordinary growth, and for free expression.
Michael Masnick, TechDirt: The Definitive Post On Why SOPA And Protect IP Are Bad, Bad Ideas 
SOPA & PIPA don't attack the real problem, do nothing to build up the services that do solve the problem, and won't work from a technological standpoint. And that's just if we look at the what these bills are supposed to do.
The real fear is the massive collateral damage these bills will have to jobs, the economy and innovation
Jerry Brito, TIME: Congress's Piracy Blacklist Plan: A Cure Worse than the Disease? 
There are many reasons to dislike these anti-piracy bills—from overly broad definitions of what counts as infringement, to how they may shift the burden of policing from content owners to the service providers—yet the proposed meddling with the Internet's Domain Name System is the most alarming.
Ryan Chisolm, Billboard: SOPA/Protect-IP Acts Fuels the Fire of Disgruntled Music Fans 
As a music manager with clients who own their publishing and some that own their masters, I've followed closely the debates around intellectual property legislation currently being considered by Congress. Both bills have stated goals of diminishing piracy, which I'm in favor of. Unfortunately, both bills also raise very real concerns.
James Losey and Sascha Meinrath, Slate: The Internet’s Intolerable Acts 
[The PROTECT IP Act and SOPA would] undermine participatory democracy and human rights, which is why these bills have garnered near-universal condemnation from both human rights groups and technologists.
Stewart Baker, Former NSA General Counsel and Head of Cyber Policy for DHS, The Volokh Conspiracy: Copyright bills could kill hopes for secure Net 
Critics of the Stop Online Piracy Act (H.R. 3261) have had an impact. A manager’s amendment has been offered by Lamar Smith, R-TX, the Judiciary Committee chairman. I was critical of the first version. Here’s my take on the new version … [T]he new version would still do great damage to Internet security, mainly by putting obstacles in the way of DNSSEC, a protocol designed to limit certain kinds of Internet crime.
Paul Vixie, Danny McPherson, Dan Kaminsky, David Dagon, and Steve Crocker, The Hill: Mandates can't alter facts 
The DNS provisions of this pending legislation are fundamentally incompatible with security features now being added to the Domain Name System after a decade and a half of preparation. Whereas the Internet technical community has been working for fifteen years to make it possible for a web browser to know when it is being lied to by DNS, Congress now proposes that such lies become the law of the land.
[SOPA] appears to impose sweeping new risks and responsibilities on websites offering legitimate online services and to give rights holders a powerful new club to wield against any online service they believe isn't doing enough to police infringement.
Electronic Frontier Foundation: Disastrous IP Legislation Is Back – And It’s Worse than Ever 
[SOPA] would not only sabotage the domain name system but would also threaten to effectively eliminate the DMCA safe harbors that . . . have spurred much economic growth and online creativity.
Public Knowledge: House Version of Rogue Websites Bill Adds DMCA Bypass, Penalties for DNS Workarounds 
SOPA is significantly worse than its Senate cousin. This isn’t just because it uses more expansive definitions or broader language; it makes fundamental changes to who faces liability for copyright infringement.
The Business Software Alliance: SOPA Needs Work to Address Innovation Considerations 
As it now stands, however, it could sweep in more than just truly egregious actors. To fix this problem, definitions of who can be the subject of legal actions and what remedies are imposed must be tightened and narrowed. Due process, free speech, and privacy are rights cannot be compromised. And the security of networks and communications is indispensable to a thriving Internet economy. Some observers have raised reasonable questions about whether certain SOPA provisions might have unintended consequences in these areas. BSA has long stood against filtering or monitoring the Internet.
Jennifer Rubin, The Washington Post: Overkill on Internet piracy 
The bill is unnecessarily overbroad and a formula for a host of undesirable and unintended consequences.
Erick Erickson, RedState: Stopping SOPA 
Congress has proven it does not understand the internet. Perhaps they will understand brute strength against them at the ballot box.
If members of Congress do not pull their name from co-sponsorship of SOPA, the left and right should pledge to defeat each and every one of them.
Reason Magazine: New Anti-Piracy Legislation Would Break the Internet Without Stopping Piracy 
There’s so much wrong with Congress’s new anti-piracy legislation that it’s hard to know where to start.
The Weekly Standard: MPAA Head Chris Dodd on Online Censorship Bill: China's the Model 
If you're wondering why lawyers and Hollywood folks would get behind legislation to censor the Internet, you only need to listen to former Senator Chris Dodd, now the head of the MPAA, who last week explained to Variety that the lobby is only asking for the same kind of power to censor the Internet as the government has in the People's Republic of China.
Technology Liberation Front: Preliminary Thoughts on Stop Online Piracy Act 
While I’m all for shutting down websites operated by criminal enterprises, not all websites used to facilitate crimes are guilty of wrongdoing.
Harvard Business Review: The Great Firewall of America 
There is the broader message America would be sending to the rest of the world: that it's OK for Governments to set up internet censorship apparatus.
Doc Searls, Harvard Law School Blog: If you hate Big Government, fight SOPA. 
SOPA is a test for principle for members of Congress. If you wish to save the Internet, vote against it. If you wish to fight Big Government, vote against it. If you wish to protect friends in the 'content' production and distribution business at extreme cost to every other business in the world, vote for it.
Bill Wilson, President, Americans for Limited Government, The Hill: Internet piracy bill: A free speech 'kill switch' 
SOPA is the equivalent of curing a headache with a guillotine. It may stop piracy, but it would shut down our economy and unconstitutionally erode our most basic freedoms in the process.
Casey Rae-Hunter, Deputy Director, Future of Music Coalition, The Hill: Online piracy bills are flawed 
The definitions in SOPA, for example, are so overly broad as to include sites and services that musicians, filmmakers, writers and millions of other Americans use every day. We’re not doing artists — and fans — any favors by forcing sites that serve up user-generated content to police their networks for fear of liability.
Copyblogger: The Problem with SOPA (And How to Stop It) 
The last thing in the world we need right now is a law that puts small businesses, especially small web-based businesses, in danger.
Particularly when those businesses haven’t done anything wrong.
Internet Society: Statement regarding DNS blocking or filtering by ISPs in order to protect the interests of copyright holders 
In short, the negative impact of DNS filtering far outweighs any short-term, narrow, legal, or commercial benefits.
Fred Wilson, Principal of Union Square Ventures, A VC: Protecting the Safe Harbors of the DMCA and Protecting Jobs 
Big companies . . . can afford to defend themselves from litigious content companies. But three person startups cannot. And Facebook, Twitter, and YouTube were three person startups not so long ago. If they had not had the protection of the safe harbors of the DMCA, they could have been litigated out of business before they even had a chance to grow and develop into the powerhouses they have become. And venture capitalists will think more than twice about putting $3mm of early stage capital into startups if they know that the vast majority of the funds will go to pay lawyers to defend the companies instead of to hire engineers to create and build product.
Future of Music Coalition: Coming Clean on SOPA 
As an organization that wants to ensure that artists can maximize the value of their copyrights, FMC is interested in any legislative or policy proposal that would help musicians protect their rights online. However, this bill, like many that have come before, raises serious concerns about unintended consequences. Therefore, we cannot support SOPA in its current form.
American Center for Law and Justice: New Government Attempts to Control and Stifle the Internet 
These bills . . . would mark a fundamental change in how the government regulates the Internet.
Jim Fruchterman, Founder and CEO, Benetech: Why I’m Scared of the SOPA bill 
Benetech, is a leading nonprofit organization based in Silicon Valley. We write software for people with disabilities as well as human rights and environmental groups. We’re against piracy, and have made commitments to authors and publishers to encourage compliance with copyright law. So, we shouldn’t have anything to fear from a bill entitled 'Stop Online Piracy Act,' right? Unfortunately, that’s not the case.
CDT: SOPA Summary, Problems & Implications 
SOPA is the House companion to the Senate's PROTECT IP Act and shares that bill's significant problems; in addition, SOPA sweeps much more broadly and would chill online innovation and expression by creating major new litigation risks for service providers currently protected by the DMCA safe harbor.
Steve Crocker, David Dagon, Dan Kaminsky, Danny McPherson, Paul Vixie: Security and Other Technical Concerns Raised by the DNS Filtering Requirements in the PROTECT IP Bill 
Combating online infringement of intellectual property is without question an important objective. The authors of this paper take no issue with the lawful removal of infringing content from Internet hosts with due process. But while we support the goals of the bill, we believe that the use of mandated DNS filtering to combat online infringement raises serious technical and security concerns.
Brookings: Cybersecurity in the Balance: Weighing the Risks of the PROTECT IP Act and the Stop Online Piracy Act 
This will be the first legislation that pits our cybersecurity priorities against entrenched economic interests, highlighting a very real social choice. Congress’ actions on PROTECT IP and SOPA will offer some insight into whether policymakers are genuinely prepared to take cybersecurity seriously.
The Heritage Foundation: Online Piracy and SOPA: Beware of Unintended Consequences 
The legislation addresses a legitimate problem, but it may have unintended negative consequences for the operation of the Internet and free speech.
ACLU: Written Statement for the Record 
We urge Committee members to focus not just on the goal of protecting copyright owners, but also protecting the speech rights of consumers and providers who are reading and producing wholly non-infringing content and to eliminate the collateral damage to such protected content. Only in that way will the Committee truly achieve its goal of protecting authors and allow the legislation to survive constitutional challenge.
NetCoalition: Step-by-step analysis 
SOPA is an 80-page Internet regulatory proposal that goes well beyond what supporters originally sought from Congress: finding a way to target the 'worst-of-the-worst' offshore sites that peddle illegal goods to U.S. consumers by operating outside of the Department of Justice’s jurisdiction.
EDUCAUSE: Higher Education Concerns About the Stop Online Piracy Act ("SOPA"), with Initial Suggestions for Addressing Them 
SOPA goes beyond . . . reasonable, pragmatic mechanisms for addressing infringement by casting its net more widely. This overbroad response not only incorporates problems previously identified with the PROTECT IP Act, it makes those worse and creates further problems.