Wikipedia founder Jimmy Wales says the online encyclopaedia will black out its website tomorrow to protest at anti-piracy legislation under consideration in the US Congress.
Mr Wales announced the move on Twitter.
"Student warning! Do your homework early. Wikipedia protesting bad law on Wednesday!" he said in a tweet.
Wikipedia will shut down its English versions for 24 hours in protest at the controversial Stop Online Piracy Act and the Protect Intellectual Property Act.
The legislation is designed to crack down on sales of pirated US products overseas. Critics say it could hurt the technology industry and infringes on free-speech rights.
Speaking to the New York Times, Mr Wales said that the Wikipedia community hoped to send a clear message to Washington that people who worked on the internet and used it daily were not happy about the potential effects of the bills.
Wikipedia is not the first website to announce plans to shut down but is the most well-known, with an estimated 25 million visitors a day. Reddit, Boing Boing and other online sites also have plans to go dark.
