Reddit.com shut down its social news service for 12 hours. Other sites made their views clear without cutting off surfers. Google blacked out the logo on its home page, directing surfers to a page where they could add their names to a petition against the bills.
Local listings site Craigslist took a middle route, changing its local home pages to a black screen directing users to an anti-legislation page. After 10 seconds, a link to the main site appears on the home page, but some surfers missed that and were fooled into thinking the whole site was blacked out.
The Internet companies are concerned that the Stop Online Piracy Act in the House and the Protect Intellectual Property Act under consideration in the Senate, if passed, could be used to target legitimate sites where users share content.
The 24-hour Wikipedia blackout is an unprecedented move for the online encyclopedia. The decision was reached after polling the community of contributors, but dissenters say political advocacy undermines the site's mission as a neutral source.
There's also a "mirror" or copy, of Wikipedia called The Free Dictionary, but it's not up to date.
Wikipedia for mobiles: http://en.m.wikipedia.org/
"Mirror" site of Wikipedia: http://encyclopedia.thefreedictionary.com/