The Stop Online Piracy Act (SOPA) (originally known as the E-PARASITE Act) and its Senate counterpart the PROTECT IP Act (PIPA) (originally the Combating Online Infringement and Copyright Act (COICA)) were a series of bills promoted by Hollywood in the US Congress that would have a created a "blacklist" of censored websites. These bills were defeated by an enormous online campaign started by EFF and a handful of other organizations, which culminated in the Internet Blackout on the January 18, 2012.

Although the bills were ostensibly aimed at reaching foreign websites dedicated to providing illegal content, their provisions would allow for removal of enormous amounts of non-infringing content including political and other speech from the Web. The various bills defined different techniques for blocking “blacklisted” sites. Each would interfere with the Internet's domain name system (DNS), which translates names like "www.eff.org" or "www.nytimes.com" into the IP addresses that computers use to communicate. SOPA would also allow rightsholders to force payment processors to cut off payments and advertising networks to cut ties with a site simply by sending a notice.

These bills are targeted at "rogue" websites that allow indiscriminate piracy, but use vague definitions that could include hosting websites such as Dropbox, MediaFire, and Rapidshare; sites that discuss piracy such as pirate-party.us, p2pnet, Torrent Freak, torproject.org, and ZeroPaid; as well as a broad range of sites for user-generated content, such as SoundCloud, Etsy, and Deviant Art. Had these bills been passed five or ten years ago, even YouTube might not exist today — in other words, the collateral damage from this legislation would be enormous.

There are already laws and procedures in place for taking down sites that violate the law. These acts would allow the Attorney General, and even individuals, to create a blacklist to censor sites when no court has found that they have infringed copyright or any other law.

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