Today is the most popular destinations on the Internet is Blackout of Wikipedia. Main cause of this strike is protesting against SOPA and PIPA. Wikipedia blacked out to protest certain pending U.S. legislation regarding internet exchanges of information. If you want to read your search and pages in Wikipedia then for your information they are covered with a blackout a few seconds later. The wikipedia pages still load on your browser simply reload it and then hit “stop” on the browser so the blackout page doesn’t load.
You can read detail about this protesting against SOPA and PIPA in below links.
http://en.wikipedia.org/wiki/Wikipedia:SOPA_initiative/Learn_more
http://wikimediafoundation.org/wiki/English_Wikipedia_anti-SOPA_blackout