NEW YORK— Can the world live without Wikipedia for a day? The shutdown of one of the Internet’s most-visited sites is not sitting well with some of its volunteer editors, who say the protest of anti-piracy legislation could threaten the credibility of their work.

“My main concern is that it puts the organization in the role of advocacy, and that’s a slippery slope,” said editor Robert Lawton, a Michigan computer consultant who would prefer that the encyclopedia stick to being a neutral repository of knowledge. “Before we know it, we’re blacked out because we want to save the whales.”

Wikipedia’s English-language site shut down today for 24 hours.

Instead of encyclopedia articles, visitors to the site see a stark black-and-white page with the message: “Imagine a world without free knowledge.”

It is the first time the English site has been blacked out. Wikipedia’s Italian site came down once briefly in protest to an Internet censorship bill. The bill did not advance.

The protest is aimed at the Stop Online Piracy Act in the House and the Protect Intellectual Property Act in the Senate.

Both bills are designed to crack down on sales of pirated American products overseas, and they have the support of the film and music industries.