Jon Swartz

USA TODAY

SAN FRANCISCO — For a second day, popular file-sharing website Pirate Bay — which hosts copies of movies soon after their theatrical release, sometimes illegally — remained offline after being blocked by one of the world's largest Internet service providers.

Pirate Bay was inaccessible after ISP Cogent Communications blocked the IP addresses assigned to Pirate Bay by Cloudflare, an Internet security firm that protects websites from distributed denial of service attacks and other security threats.

Cogent took the action to comply with a court order in Spain in February that is unrelated to copyright infringement. The company had no comment.

Sites such as Pirate Bay are often called torrent sites because they are used to download relatively large files from a network of other users. This file-sharing is reminiscent of music sharing site Napster, which rose to prominence at the turn of the millennium.

Cloudflare is huddling with Cogent to prevent mass blocking of legitimate websites, says Doug Kramer, Cloudflare's general counsel.

"Our policy is to support an open, free and secure Internet," he says. "We're more than happy to work with courts to help them understand how the Internet works."

Visitors to Pirate Bay's website have encountered the following message: “This page (https://thepiratebay.org/) is currently offline. However, because the site uses Cloudflare’s Always Online™ technology you can continue to surf a snapshot of the site. We will keep checking in the background and, as soon as the site comes back, you will automatically be served the live version."

Pirate Bay could not be reached for comment.

SInce its launch in late 2003 by Swedish anti-copyright organization Piratbyrån (The Piracy Bureau), Pirate Bay has been dogged by controversy.

In April 2009, co-founders Peter Sunde, Fredrik Neij and Gottfrid Svartholm were found guilty in Sweden for assisting copyright infringement, fined and sentenced to one year in prison. Svartholm, Neij and Sunde were released after serving shortened sentences.

The site, which has sparked debate about the legality of file sharing and copyright issues, has become a platform for political initiatives against established intellectual-property laws. It has faced previous shutdowns and domain seizures.

It and other torrent sites have vexed Hollywood’s biggest studios for years, costing them billions of dollars in potential ticket sales and rentals.

A legal solution may be on the way. Six of the seven largest studios, led by Warner Bros, are proposing to roll out movies to video on-demand services as soon as 17 days after theatrical release, according to a report in Variety.

Follow USA TODAY's San Francisco Bureau Chief Jon Swartz @jswartz on Twitter.