The Bills in Congress: PIPA is a Senate bill originally called the Protect IP Act. “IP” is short, in this case, for Intellectual Property, such as movies, music or writing that, in the digital age, can easily be copied and transmitted online without payment to their creators. SOPA — the Stop Online Piracy Act — is a similar bill in the House. The idea of both, as described by their sponsors, was to stop the illegal copying of movies or music, something that Hollywood studios, music publishers and many others believe is threatening their businesses. Supporters range from the Country Music Association to the U.S. Chamber of Commerce, from the Motion Picture Association of America to the AFL-CIO. But not everyone agrees. These bills pitted Hollywood against the goals of many in Silicon Valley.
Wikipedia Blackout - Intellectual Property Rights Advocates Quest For Internet Censorship
Most educational institutions don't allow Wikipedia to be used in citations and in 9 hours neither will anyone else on the Internet due to congressional action being considered that could drastically change the face of the Internet.
In the digital age of aggregation and curation technology mashing up the information superhighway comes a group who wants to block re-distribution of creative assets.