Wikipedia co-founder Jimmy Wales announced on Monday that the free online encyclopedia will go dark for 24 hours on Jan. 18, in protest over Stop Online Piracy Act (SOPA), an anti-piracy bill under consideration before the Congress.

“Only the English version of web encyclopedia will be down for 24 hours, from Tuesday midnight Washington DC time until Wednesday Midnight, while the Germans will run a banner and other languages will make their own decision,” Wales said on his Twitter.

According to comScore estimates, the English Wikipedia alone accounts for 25 million average daily visitors globally.

Currently under consideration before the Congress, SOPA would enable U.S. law enforcement more power to inhibit free speech and innovation on the Internet and introduce new measures for censorship of international Web sites inside the United States.

“Over the course of the past 72 hours, over 1800 Wikipedians have joined together to discuss proposed actions that the community might wish to take against SOPA and PIPA (Protect IP Act). This is by far the largest level of participation in a community discussion ever seen on Wikipedia, which illustrates the level of concern that Wikipedians feel about this proposed legislation,” said Sue Gardner, Wikimedia Foundation Executive Director, in a press release.

Wikipedia is not the only Web site to shutdown. Companies such as Reddit, BoingBoing, WordPress, Craiglist, Mozilla, Cheezburger network, Minecraft and several other Web sites related to video games will be shutdown on the Jan. 18 “black out” protest.

This is the first time that the English Wikipedia has ever staged a public protest of this nature. However, Wikipedia took down its Italian site last year in protest over a proposed law that, if agreed, would have made it a criminal offence to publish the results of police wiretaps. The strike caused the Italian parliament to back down.