Wikipedia has closed down its English-speaking site as promised in protest over the controversial Sopa and Pipa legislation, which the website believes threatens to censor the internet.
The Stop Online Piracy and Protect Intellectual Property Acts are intended to protect copyright holders - such as record labels and film companies - from illegal sharing of their products through websites such as Facebook and YouTube, but the acts have been heavily criticised.
Displaying nothing but a black page and a short message, the English Wikipedia page reads: "Imagine a world without free knowledge. For over a decade, we have spent millions of hours building the largest encyclopedia in human history.
"The US Congress is considering legislation that could fatally damage the free and open internet. For 24 hours, to raise awareness, we are blacking out Wikipedia."
The page includes links to Facebook, Google+ and Twitter, where Wikipedia hopes that its users will share their support for the blackout.
Contrary to popular belief that Sopa has been cancelled, Wikipedia explains that neither bill is dead and that "on 17 January 17, Sopa's sponsor said the bill will be discussed in early February. There are signs Pipa may be debated on the Senate floor next week.
"Moreover, Sopa and Pipa are just indicators of a much broader problem. We are already seeing big media calling us names ... We want the internet to be free and open, everywhere, for everyone."
The social news site Reddit is also planning a blackout, due to begin at 1pm GMT and last for 12 hours, during which time the website will be unavailable.
Blogging platform Wordpress, while not blacking out completely, has created a new landing page at wordpress.org announcing the site's protest against the acts; the landing page includes an informational video explaining what Protect IP (Pipa) is and how it has the potential to block entire websites because of one copyright infringement.
These infringements include trivial offences like playing copyrighted music in the background of a video, or singing a song.
In further protest against Sopa and Pipa, numerous bloggers have blacked out their own personal blogs and taken to Twitter to show their support of the global blackouts.
Finally, American blogging network Boing Boing has replaced its site with an error message saying that the proposed legislations would "certainly kill us forever", while Google - although not blacking out - has issued a statement called "Don't censor the web."
Google adds: "These bills wouldn't get rid of pirate sites. Pirate sites would just change their addresses in order to continue their criminal activities. There are better ways to address piracy than to ask U.S. companies to censor the Internet."