The English language Wikipedia receives an average of more than 25 million daily visitors from around the world, according to comScore data.
The service will be the highest profile name to join a growing campaign that will see it black out its pages so visitors will only see information about the controversial Stop Online Piracy Act (Sopa) and the Protect Intellectual Property Act (Pipa).
"When you are trying to do your research paper, when you are just trying to find some factual information and a lot of people rely on Wikipedia, it won't be there," said Lance Ulanoff, editor in chief of online news site Mashable.
"They'll basically come to a message that says they've gone dark in protest."
Smaller site Boing Boing has also blacked out its pages, with those behing Reddit.com have promised to do the same.
Search engine Google will not black out its pages but a link will be placed on their homepage connecting to information about why Sopa may not be a good thing.
Google has repeatedly said the bill goes too far and could hurt investment.
Along with other Internet companies such as Yahoo, Facebook, Twitter and eBay, it has run advertisements in major newspapers urging Washington lawmakers to rethink their approach.
The Sopa legislation under consideration in the House of Representatives and Pipa in the Senate aims to crack down on online sales of pirated American movies, music or other goods by forcing internet companies to block access to foreign sites offering material that violates US copyright laws.
Advertising networks could also be required to stop online ads, while search engines would be barred from directly linking to websites found to be distributing pirated goods.
The proposed laws would also force some websites offline.
How it will work:
US Attorney's office will have the power to order internet providers not to carry offshore sites it deems illegal
What providers will have to do:
Monitor customers' traffic and block web sites suspected of copyright infringement
Who supports Sopa:
The music recording industry, Hollywood film companies, police and firefighters among others
Who is against Sopa:
Most of the internet industry including Google, Facebook, Twitter, eBay and LinkedIn
Source : Sky News 18th January 2012
