Today more than 50 venture capitalists — from forty firms which have funded many of today’s most popular Internet companies — have announced their opposition to S968, Senator Leahy’s PROTECT IP (PIPA) Act. In a letter to Congress, the financiers noted PIPA, “will stifle investment in Internet services, throttle innovation, and hurt American competitiveness.” The new business opponents join free speech advocates and companies like Google in pushing back against this dangerous legislation.

You can read the letter and urge your lawmakers to oppose PROTECT IP by clicking here.

PIPA would give the government the power to force Internet service providers, search engines, and other “information location tools” to block users’ access to sites that have been accused of copyright infringement — initiating a China-like censorship regime here in the United States.

As one signer of the letter noted, “The signatories to this letter work for firms that manage over $13B. We are early investors in services like Facebook, Twitter, Zynga, Skype, Groupon, LinkedIn, Tumblr, Foursquare, and a host of other important web services. The services we have backed now reach over a billion users.”

In particular, the letter’s authors worry that:

1) By requiring “information location tools” — potentially encompassing any “director[ies], index[es], reference[s], pointer[s], or hypertext link[s]” — to remove access to entire domains, the bill puts burdens on countless Internet services.

2) By requiring access to sites to be blocked by Domain Name System providers, it endangers the security and integrity of the Internet.

3) The bill’s private right of action will no doubt be used by many rights-holders in ways that create significant burdens on legitimate online commerce services. The scope of orders and cost of litigation could be significant, even for companies acting in good faith.  Rights-holders have stated their interest in this private right of action because they worry that the Department of Justice will not have enough resources to initiate actions against all of the infringing sites.  Yet, why should costs be shifted to innocent Internet entrepreneurs, most of whom have budgets smaller than the Department of Justice’s?

The more Americans have heard about the details of Leahy’s PROTECT IP bill, the more we’ve seen them come out against this dangerous Internet censorship effort. The very people who made the Internet as we know it today possible are opposing this bill — and that should trouble anybody who claims to care about protecting American jobs.

You can read the letter and urge your lawmakers to oppose PROTECT IP by clicking here.

More than 350,000 people have signed Demand Progress’s petitions against PIPA and the Combating Online Infringement and Counterfeits Act — an earlier version of the same bill. Over 50,000 members emailed their lawmakers last week to demand that they join Senator Wyden in opposing the bill. And more than 6,000 Demand Progress members have called their lawmakers to urge them to oppose PIPA.