If some websites you visit today appear different than usual or are unavailable, don't complain to your Internet provider.
The operators of the websites may be involved in a protest.
Google and numerous websites planned to place links and statements on home pages today to protest two pieces of anti-piracy legislation under consideration by Congress.
Some sites -- including the online encyclopedia Wikipedia and Pittsburgh-based RentJungle.com -- are taking the protest a step further by participating in a daylong "blackout" to voice opposition to the Stop Online Piracy Act, which is in the House, and the Protect IP Act that is under consideration by the Senate.
The measures are being pushed by the Motion Picture Association of America, the movie industy's trade group, and the U.S. Chamber of Commerce, the nation's largest business-lobbying group, which are trying to stop the sales of pirated American entertainment products overseas.
"We decided to shut down to show how detrimental these bills will be to the freedoms that we have on the Internet," said George Wong, a co-founder of RentJungle.com, which helps apartment hunters find the housing they want. "These bills not only have the potential of hurting companies like ours, they will result in people being less likely to innovate."
Jimmy Wales, co-founder of Wikipedia, called the decision to shut down the widely viewed website an "extraordinary" action in response to the proposed laws, which he believes will "endanger free speech both in the United States and abroad, and set a frightening precedent of Internet censorship for the world."
Samantha Smith, a Google spokeswoman, said in an e-mail on Tuesday that company officials "oppose these bills because there are smart, targeted ways to shut down foreign rogue websites without asking American companies to censor the Internet."
She said Google respects copyright.
"Last year, we took down 5 million infringing Web pages from our search results and invested more than $60 million in the fight against bad ads," Smith said.
Supporters of the laws believe U.S. companies need to be protected from Internet pirates who copy and distribute illegal copies of movies and other electronic media.
"Congress cannot stand by and do nothing while some of America's most profitable and productive industries are under attack," said Rep. Lamar Smith, a Texas Republican who chairs the Judiciary Committee.
David Farber, a professor of computer science and public policy at Carnegie Mellon University, called the proposed legislation "a dangerous game that is trying to solve a non-problem."
"One of the biggest problems I see with these laws is the lack of due process," he said. "I'm not a lawyer, but as I understand it, these measures could give some government bureaucrat or attorney the power to issue and order blocking access to a website that has been accused of allowing copyrighted material on its servers even if the operator had no knowledge of it."
Nathan Good, director of software engineering for the Pittsburgh-based ShowClix, which sells tickets to events online, said that while his company cannot "go dark" for a day because of contracts it has with clients, it supports the blackout as a way to raise awareness of opposition to the legislation.
"We certainly believe in protecting copyrighted material," he said. "But the laws that are being considered are like using a chain saw to scratch an itch."
Good said there are viable alternatives to protect copyrighted materials.
"One good way to prevent pirating is to offer high-quality alternatives to music, videos and film at reasonable prices," he said.
Making material available via "streaming" services that allow customers to view or listen to material without having to download it to their computers also is a way to prevent theft, Good said.
