- For details on the Wikipedia blackout that is currently ongoing, please see Wikipedia:SOPA initiative.
The originally proposed bill would allow the U.S. Department of Justice, as well as copyright holders, to seek court orders against websites accused of enabling or facilitating copyright infringement. Depending on who makes the request, the court order could include barring online advertising networks and payment facilitators from doing business with the allegedly infringing website, barring search engines from linking to such sites, and requiring Internet service providers to block access to such sites. The bill would make unauthorized streaming of copyrighted content a crime, with a maximum penalty of five years in prison for ten such infringements within six months. The bill also gives immunity to Internet services that voluntarily take action against websites dedicated to infringement, while making liable for damages any copyright holder who knowingly misrepresents that a website is dedicated to infringement.
Proponents of the bill say it protects the intellectual property market and corresponding industry, jobs and revenue, and is necessary to bolster enforcement of copyright laws, especially against foreign websites. They cite examples such as Google's $500 million settlement with the Department of Justice for its role in a scheme to target U.S. consumers with ads to illegally import prescription drugs from Canadian pharmacies.
Opponents say that it violates the First Amendment, is Internet censorship, will cripple the Internet, and will threaten whistle-blowing and other free speech actions. Opponents have initiated a number of protest actions, including petition drives, boycotts of companies that support the legislation, and planned service blackouts by English Wikipedia and major Internet companies scheduled to coincide with the next Congressional hearing on the matter.
The House Judiciary Committee held hearings on November 16 and December 15, 2011. The Committee was scheduled to continue debate in January 2012, but on January 17 Chairman Smith said that "[d]ue to the Republican and Democratic retreats taking place over the next two weeks, markup of the Stop Online Piracy Act is expected to resume in February."
For more detail about it, you can read in wikipedia