Simply put, they would give copyright holders new ways to punish websites that host pirated content.

Both bills originally empowered  holders to request orders that would block access to foreign websites accused of hosting pirated content.

That means that users within the U.S. would essentially see an error message when they try to visit that website, though users in other countries would still be able to visit it. This provision has been removed from SOPA pending “further examination,” though it’s still included in PIPA.

SOPA also requires search engines to delete links to offending websites from their search results, while PIPA does not.

Both bills require advertisers and payment services not to do business with sites accused of piracy. They also allow internet service providers to pre-emptively block websites they believe are dedicated to piracy.

SOPA and PIPA target websites whose servers are hosted or whose domain names are registered outside of the U.S. While supporters of the bills say that this shouldn’t have any effect on American websites, many American companies have domain names registered overseas — think of all the sites that end in letters like .ly. Though no one knows how the bills would ultimately be enforced if they became law, critics argue that domestic sites could be slammed with SOPA/PIPA-related lawsuits, and that the increased legal costs involved in running a website would raise a higher bar to founding an internet startup.

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