A hyperlink to an illicit digital stash of Playboy centerfolds is at the heart of a copyright infringement lawsuit that could have major consequences for internet users and publishers (though legal observers do not expect such an outcome).

In February of 2016, the blog Boing Boing linked to a complete collection of the adult magazine’s centerfolds that had been uploaded, without permission, to the websites Imgur and YouTube. In the post (aptly titled “Every Playboy Playmate Centerfold Ever”) Boing Boing editor Xeni Jardin said that the hundreds of images allow you to “see how our standards of hotness, and the art of commercial erotic photography, have changed over time.”

Even though Boing Boing had not uploaded or hosted the unauthorized images itself, Playboy sued the website’s holding company Happy Mutants over the article. The lawsuit resurfaces previously settled questions about whether a simple link to material uploaded or hosted by a third party—a ubiquitous and foundational element of the internet—can constitute copyright infringement.

Playboy argues that it can. “By undertaking substantial promotional efforts to encourage visits to the infringing material” through its post, Boing Boing “materially contributed to the infringing conduct,” the complaint reads.

The Electronic Frontier Foundation (EFF), which is representing Happy Mutants, moved to dismiss the lawsuit last week , asserting there is no legal basis for the links to be considered copyright infringement. The foundation warns of major upheaval for the web as we know it if publishers and journalists who post links must screen them for infringing material.

“If Playboy succeeds, it’s going to have ramifications far beyond Boing Boing,” said Corynne McSherry, EFF’s legal director. “It’s going to have an impact all over the internet.”

Playboy’s suit has left some observers baffled—not because the magazine is advancing complex new legal theories, but because courts have already established that linking to infringing material uploaded by third parties does not constitute copyright infringement.

“The U.S. legal system has sorted all this out,” said Adam Holland, a project manager at Harvard University’s Berkman Klein Center for Internet & Society. “There’s no new theory, there’s no new weird set of facts.”

Playboy declined to comment for this piece.

A key precedent protecting linking also involves pornography. In the suit Perfect 10, Inc. v. Amazon.com, Inc., the Court of Appeals for the Ninth Circuit ruled in 2007 that Google, which was a defendant in the suit, wasn’t liable for copyright infringement over linking to third party websites hosting explicit images owned by the adult website Perfect 10 because those images were not actually held by the search engine.

Similarly, the EFF motion argues, Boing Boing did not store the Playboy centerfolds in question. The motion also notes that the website only published links to the photos after they had been uploaded to Imgur and YouTube, and therefore could not have induced or caused the infringement.

Under the Digital Millennium Copyright Act (DMCA), Playboy can send notices to both Imgur and YouTube requesting they take down the centerfolds—which both sites have done. (The Lumen Database, which Holland manages, collects such DMCA and other takedown records, when made publicly available). Playboy could also sue the person who uploaded the images. But Imgur and YouTube cannot be hauled to court for copyright infringement because they are essentially middlemen not legally liable for user-submitted content—a legal protection enshrined in the “safe harbor” provisions of the DMCA.

and But Playboy’s Dutch publisher did find success in a similar lawsuit heard in a European courtroom in September 2016. In that case, the Court of Justice of the European Union found that Dutch website GeenStijl had violated copyright law by linking to a website that illegally hosted Playboy photographs. The court ruled that commercial companies linking to infringing material for financial gain “should carry out the checks necessary to ensure that the work concerned is not illegally published.” The decision met with criticism concern from some in the legal and tech fields, though the ruling will not impact non-commercial social media users.

In the U.S., a lawsuit over a photograph of Tom Brady posted to Twitter is also testing whether links can constitute copyright infringement. The photo of the football star, taken by Getty photographer Justin Goldman in 2016, was uploaded to the social media website without Goldman’s permission. Several media outlets—including Vox and the Boston Globe—then embedded that tweet in their news articles. Goldman sued the publications, alleging that the embeds amounted to copyright infringement. The EFF has filed an amicus brief on behalf of the defendants.

Both cases are notable because they involve journalists. Even if the Boing Boing lawsuit is dismissed before a trial, McSherry said, battling such cases is an arduous burden to place on publications, some of which might not have similar resources available to defend themselves.

Should the court indeed find that the links are copyright infringement, as an online publication Boing Boing is protected by fair use, the EFF motion asserts. “They were reporting on the existence of a collection of works and commenting on it,” said McSherry. “That’s pretty classic fair use.”