( CNN ) -- Wikipedia was back Thursday , a day after shutting down the website to protest anti-piracy bills now in Congress . On the website early Thursday morning was the cryptic message : `` Thank you for protecting Wikipedia . We 're not done yet . '' Clicking on that message takes a Wikipedia viewer to a thank you letter and instructions on how to continue fighting against anti-piracy bills that critics say could amount to censorship . `` Your voice was loud and strong , '' the message said . `` Millions of people have spoken in defense of a free and open Internet . '' Wikipedia was among several websites to shut down Wednesday in protest of the bills . Instead of the usual encyclopedia articles , visitors to Wikipedia 's English-language site were greeted by a message about the decision to black out its Web page for an entire day . Why Wikipedia went down at midnight . However , users were able to access Wikipedia on some smartphones . The site and several others went dark at midnight Tuesday ; others followed suit later in the day . The protest is in response to the Stop Online Piracy Act bill , a piece of proposed legislation that is working its way through the Congress . A Senate committee approved a similar bill in May called the Protect IP Act , which is now pending before the full Senate . The controversy over SOPA and PIPA has turned into an all-out war between Hollywood and Silicon Valley . Media companies have united in favor of the bills , while tech 's power players are throwing their might into opposing them . `` Both SOPA and PIPA are threats not just to the U.S. economy , and not just to all the jobs that this tech sector creates , but if they had existed , Steve Huffman and I could have never founded Reddit , '' said Alexis Ohanian , who co-founded the site . Millions visit Reddit to submit interesting links from websites , discuss them and vote on them , he said , calling it `` sort of a democratic front page of the web . '' Reddit also went dark Wednesday morning and was back Thursday . One member of Congress , Rep. Darrell Issa , R-California , who opposes the bills , said the unprecedented blackouts had `` turned the tide against a backroom lobbying effort by interests that are n't used to being told no . '' Issa is pushing for consideration of his own plan , the OPEN act , addressing the matter . CNN 's Ed Payne , Julianne Pepitone , John D. Sutter , Ted Barrett and Deirdre Walsh contributed to this report .
The protest is in opposition to the Stop Online Violence Act legislation . ` ` We 're not done yet , '' website says . The legislation is working its way through Congress .