Last week we reported that Reddit.com, the link sharing site, will be going dark for eight hours tomorrow. The site is protesting the Stop Online Piracy Act (SOPA) and PROTECT IP Act (PIPA) that’s being debated in the House and Senate. At the time, Wikipedia was thinking about joining the blackout, and now it has confirmed that it will also be shuttered. No English-language Wikipedia sites will be accessible for 24 hours, starting at midnight tonight.

Wikipedia’s founder, Jimmy Wales, tweeted that the site has “25 million average daily visitors globally.” U.S. citizens visiting the site during the blackout will be encouraged to call their representatives asking them not to support the bills. Here’s a list of several sites that will also be joining protest.

One site you won’t see on that list is Twitter. The Guardian reports: “In a tweet, Twitter CEO Dick Costolo called Wikipedia’s plans to pull the plug on its website ‘foolish’ and ‘silly.’”