The Pirate Bay is one of the world's most prominent link-distributing sites, and many of the links it hosts can be used to download copyright-infringing music and movie files.
The site has begun placing a link marked 'Share on Facebook' on the page associated with each file which quickly and easily puts the link on the user's Facebook page. If someone has BitTorrent software on their computer, clicking that link will download the requested file from other computers.
Publishing links to copyright-infringing material violates Facebook's terms and conditions but liability could actually pass to the social networking giant said Struan Robertson, a technology lawyer at Pinsent Masons, the law firm behind OUT-LAW.COM.
"Not everything to which Pirate Bay links infringes copyright, but much of it does so I wouldn't be surprised if Facebook simply erred on the side of caution and blocked the sharing functionality," he said.
"Some links posted to Facebook via other sites no doubt link to infringing content and Facebook is generally not liable for these infringements; but if it is made aware of links to infringing content and refuses to remove them, it may become liable," said Robertson. "If Facebook has reason to think that the vast majority of the links from a particular partner site are links to infringing content, it would be wise to block them."
Facebook did not respond to a request for comment about whether it intends to block links posted via The Pirate Bay before publication.
The Pirate Bay does not host any actual copyrighted material but hosts links to torrent files, small files that are used to download larger files from others' computers using the peer-to-peer file-sharing protocol BitTorrent.
The Pirate Bay was recently the subject of a Swedish trial which will decide whether or not the people behind it are guilty of copyright offences.
"I wouldn't be surprised if Facebook simply erred on the side of caution and blocked the sharing functionality, at least pending the outcome of the Stockholm trial, to avoid becoming embroiled in the battle over the legality of that site," said Robertson.
This is despite the fact that Facebook could hold The Pirate Bay liable for any damage it suffers as a result of the link posting.
"Facebook's own terms say that if a site decides to offer a 'Share on Facebook' link, that site agrees to indemnify Facebook for any liability that may arise out of the content or the links posted to Facebook – i.e. if Facebook gets sued, it can, in theory, recover its losses from Pirate Bay. I don't see Facebook placing much value on that indemnity, though," said Robertson.
Robertson also warned that users who share links to infringing files via Facebook risk becoming the target of legal threats from the copyright holders.