As reported by Wiki Media Foundation:
“It is the opinion of the English Wikipedia community that both of these bills, if passed, would be devastating to the free and open web.”
On January 16, 2012, the Wikipedia community announced its decision to black out the English-language Wikipedia for 24 hours, worldwide, beginning at 05:00 UTC on Wednesday, January 18 (you can read the statement from the Wikimedia Foundation here).
The blackout is a protest against proposed legislation in the United States—the Stop Online Piracy Act (SOPA) in the U.S. House of Representatives, and the PROTECTIP Act (PIPA) in the U.S. Senate—that, if passed, would seriously damage the free and open Internet, including Wikipedia.
This will be the first time the English Wikipedia has ever staged a public protest of this nature and is not done lightly. Dozens of other high-powered sites and thousands more are joining the protest in varied ways to to speak with a collective voice. Read the full announcement