The Stop Online Piracy Act is an act of Congress that strengthens penalties for copyright infringement and piracy. It was introduced on October 17th 2011 and was signed into law on March 16, 2012.
The act led to a massive shutdown of torrenting sites in the United States, as well as stricter copyright laws. Like most nations, the U.S. does not have fair use laws, and made the strict copyright laws of the United States more punishable.