What exactly is blacked out?
The English-language version of Wikipedia is offline and has been replaced with a message related to the anti-piracy legislation going through Congress, SOPA, in the United States. Other language editions of Wikipedia will be unaffected.
Additionally, popular community website Reddit has also gone offline, as well as Boing-Boing and several smaller websites.
WordPress is suggesting users black out their own websites, but is not forcing any blackouts.
Whoa, SOPA? What the heck is that?
SOPA, which stands for the Stop Online Piracy Act, is a piece of legislation in the U.S. House of Representatives. The act is designed to target copyright infringers online through a series of harsh penalties.
In the U.S. Senate, a separate companion bill is called the Protect Intellectual Property Act or PIPA.
…Why do the SOPA opponents say it would turn the Internet into a police state?
Several of the provisions in SOPA force American Internet service providers or ISPs hosting websites to remove a site from the Internet if there’s a claim it’s infringing against copyright, even if it has not been fully proved in court. The argument is that this would make it easy for someone to make false or weak claims to take a website offline while the case makes its way through the courts.
Additionally, it would force ISPs to block non-U.S. websites accused of having infringing material, meaning sites from other countries might not be available in the United States. Opponents say this might destabilize the Internet and allow loopholes for hackers to exploit.
Which sites that I use would this affect?
Most obviously, Wikipedia. There are millions of users who constantly update the site, and sometimes things are posted that might have questionable copyright provenance. If Wikipedia were shut down or blocked every time it was challenged over copyright, the site would likely cease to function.
YouTube would be another site that would be harshly affected by the measures. Since millions of people upload videos to YouTube, sometimes copyrighted material slips through. Currently, this is dealt with by individual videos being taken down after a complaint. Google has stated YouTube probably wouldn’t exist if a SOPA-like law had been in effect in 2004 when the site launched.
Some interpretations of the bill say that sites that even link to other sites accused of infringing might be at risk.
Basically, any site that has a large user-generated component is worried about SOPA.This is the document Wikipedia references when explaining why they are against the bill.