Wikipedia and Google has joined hundreds of other websites in a sprawling online protest against legislation in the US Congress intended to crack down on Internet piracy.
Wikipedia shut down the English version of its online encyclopedia for 24 hours to protest the Stop Online Piracy Act (SOPA) introduced in the House of Representatives and the Senate version, the Protect IP Act (PIPA).
Google blotted out the celebrated logo on its US home page with a black banner and published an exhortation to users to "Tell Congress: Please don't censor the Web!''
Like Wikipedia, social news site reddit also went dark, urging visitors to call their lawmaker or sign a petition opposing the House and Senate bills.
"These bills provide overly broad mechanisms for enforcement of copyright which would restrict innovation and threaten the existence of websites with user-submitted content,'' reddit said.
Culture and technology blog Boing Boing also took itself offline to protest what it called "legislation that would certainly kill us forever.''
Reporters Without Borders shut down its English-language website for 24 hours warning that the bills "would sacrifice online freedom of expression in the name of combating piracy.''
Blogging platform WordPress.com covered its home page with black banners with the word "censored'' as did technology magazine Wired.
The popular Cheezburger humor network posted messages of opposition to the bills on all of its 58 sites, which include icanhascheezburger.com, FAIL Blog and The Daily What.
The draft legislation has won the backing of Hollywood, the music industry, the National Association of Manufacturers, the US Chamber of Commerce and other groups.
The Business Software Alliance has welcomed House efforts to curb software piracy but has said "valid and important questions have been raised about the bill.''
The Senate is scheduled to vote on PIPA on January 24 but Republican House speaker John Boehner said Wednesday there was a "lack of consensus at this point'' on SOPA, the House version, and it would need work in committee.
The bills have come under fire from digital rights and free speech groups for allegedly paving the way for US authorities to shut down websites accused of online piracy, including foreign sites, without due process.
"Right now, the US Congress is considering legislation that could fatally damage the free and open Internet,'' Wikipedia said in a message at its darkened website. "For 24 hours, to raise awareness, we are blacking out Wikipedia.''
Other Web giants such as Twitter, Facebook and Craigslist declined to shut down for the day but expressed their opposition to the legislation.
Twitter co-founder Jack Dorsey urged his 1.8 million followers to tweet, email and call and "tell Congress NO.''
Facebook said it takes online piracy and copyright infringement "very seriously'' but the bills "are not the right solution to this problem, because of the collateral damage they would cause to the Internet.''
US visitors to Craigslist were met with a message of opposition to the legislation and had to click on a link to continue on to the site.
The founders of Google, Twitter, Wikipedia, Yahoo! and other Internet giants said in an open letter last month the legislation would give the US government censorship powers "similar to those used by China, Malaysia and Iran.''
"We oppose these bills because there are smart, targeted ways to shut down foreign rogue websites without asking American companies to censor the Internet,'' a Google spokesman said.
The White House expressed concern about the anti-online piracy bills in a statement over the weekend.
"While we believe that online piracy by foreign websites is a serious problem that requires a serious legislative response, we will not support legislation that reduces freedom of expression, increases cybersecurity risk, or undermines the dynamic, innovative global Internet,'' it said.
News Corp. chief executive Rupert Murdoch, who backs the US legislation, accused the "blogosphere'' of "terrorising many senators and congressmen who previously committed'' to supporting it.
"Nonsense argument about danger to Internet. How about Google, others blocking porn, hate speech, etc? Internet hurt?'' he wrote on Twitter.