Big players in online content watch as porn site's case winds its way through US courts, wary of ramifications for wider web

A powerful lobby group that represents the interests of the biggest Hollywood movie studios has aligned itself with an obscure Miami gay porn producer, in the ongoing battle to protect copyrighted material online.

The Motion Picture Association of America (MPAA), which counts Disney, Paramount and Sony pictures among its members, is supporting a case brought by Flava Works, an adult-film studio that specializes in black and Latino productions with titles such as Raw Rods and Snow Ballerz.

The case revolves around the ongoing argument fought by far bigger players than Flava – namely, whether embedding videos on a third-party website constitutes piracy.

In the case, first brought in 2010, Flava accuses myVidster, a little-known social video bookmarking and storage service owned by Marques Gunter, of allowing its videos to be embedded without authorization.

The central question concerns how much of the burden rests with the owners of sites like myVidster. Should they merely act when notified of copyright infringements, or should they take a more proactive role in policing their websites?

Such questions have bearings on the business models of the dominant players on the internet. Last week a court in New York re-opened a case first brought by Viacom against YouTube in 2007, in which it accused the Google-owned website of being aware of the unauthorised posting of content from its hit shows including South Park, The Daily Show and The Colbert Report.

Flava's case has reached the important seventh circuit court of appeals – which is why the interest of the big boys has been piqued.

According to the original complaint by Flava, users of myVidster would routinely upload its videos to the service for others to watch.

When Flava Works sent Gunter an order to take down those copyright-protected videos, he did so. But Gunter performed no additional policing, nor did he prevent repeat offenders from re-uploading other titles by Flava Works.

Gunter, who runs the site and did not himself upload the copyrighted content in question, argues that he was protected under the Digital Millenium Copyright Act (DMCA). The DMCA says services like myVidster, Facebook, YouTube, Google and Tumblr are not accountable for copyrighted content posted by their users as long as they respond to takedown notices quickly.

But in July 2011, Illinois district court judge John F Grady granted Flava a preliminary injunction against Gunter.

"Gunter does not warn his users about copyright infringement (coyly instructing them not to violate 'US law' does not cut it)," wrote Grady in his ruling.

Grady said: "He removes videos from myVidster that are listed in DMCA notices, but goes no further. Beyond his mechanical response to the notices, Gunter refuses to concern himself with copyright protection. It is true that service providers are not required to police their sites for infringement, but they are required to investigate and respond to notices of infringement – with respect to content and repeat infringers."

This reasoning prompted Facebook and Google to jointly write a friend of the court brief, submitted in November, in support of Gunter's appeal. The judge, they argue, went too far in placing a burden of oversight on Gunter. Such a burden would be prohibitively costly and time consuming were it to fall on Google or Facebook's shoulders.

In November's brief, the companies wrote, with great portent, that the "continued development and progress of web technology" hung in the balance.

"In order to be liable as a direct infringer of the exclusive right of public performance, one must transmit or otherwise communicate the copyrighted work in question," the statement continued. "With respect to 'embedded' videos, myVidster does not transmit or otherwise communicate the copyrighted video; a third-party site does."

Now, the movie industry has fired back. In a brief filed on Friday, the MPAA backed Flava's complaint. "MyVidster users who posted embedded links to video streams directly infringed the performance right even though they did not necessarily possess a copy of the infringed work," the group wrote.

The powerful motion picture lobby concluded that myVidster actively encouraged piracy, and did nothing about known repeat offenders.

MyVidster, the MPAA argued, "advertised the availability of infringing material, including mainstream motion pictures; and willfully blinded itself to infringements by failing to take steps, like filtering, to identify re-postings of the same infringing links that Flava had already identified."

Under Grady's opinion, now supported by the MPAA, websites that embed videos from third parties – but do not even store them on their own servers – would be responsible for the posted content. Many legal scholars argue that this could create a dampening effect on free expression by dissuading sites from allowing users to post embedded content.

The MPAA did not return calls from the Guardian for comment.

Laurence Tribe, a professor of constitutional law at Harvard Law School, told the Guardian via email: "Legal regimes imposing obligations on bookmarking sites to police the content they host threaten to chill free speech to a dangerous degree. They ought to be subject to very strict standards of constitutional review, lest the open character of the internet as a platform advancing the freedom of speech be unduly compromised."