Meta's BitTorrent Fair Use Defense: A New Legal Battleground in AI Training

In a surprising legal maneuver that could reshape the boundaries of copyright law in the AI era, Meta has mounted a novel defense in its ongoing copyright lawsuit with authors. The company now argues that uploading pirated books via BitTorrent during its AI training process qualifies as fair use, claiming the distribution was technically necessary for downloading the training data.

The Bittersweet Victory

The legal battle began in 2023 when prominent authors including Richard Kadrey, Sarah Silverman, and Christopher Golden filed a class-action lawsuit against Meta. The authors alleged that Meta used their copyrighted books without permission to train its Llama language models.

Last summer, Meta achieved a significant victory when the court ruled that using pirated books to train its LLM qualified as fair use. However, this win came with a catch. The court found that Meta remained liable for downloading and sharing the books via BitTorrent, which the authors argued constituted widespread copyright infringement.

The BitTorrent Defense Emerges

In a supplemental interrogatory response filed last week, Meta introduced a new legal argument that could potentially resolve the remaining claims. The company contends that uploading pirated books to other BitTorrent users during the torrent download process also qualifies as fair use.

Meta's reasoning is straightforward: anyone using BitTorrent to transfer files automatically uploads content to others as part of the protocol's inherent design. The company argues this wasn't a choice but a technical necessity—the very nature of how BitTorrent works.

Technical Necessity or Copyright Infringement?

Meta's defense hinges on the argument that BitTorrent sharing was essential to obtain the valuable training data. According to the company, datasets from shadow libraries like Anna's Archive were only available in bulk through torrent downloads, making BitTorrent the only practical option.

"Meta used BitTorrent because it was a more efficient and reliable means of obtaining the datasets, and in the case of Anna's Archive, those datasets were only available in bulk through torrent downloads," Meta's attorney wrote.

The company frames this as "part-and-parcel" of the download process, arguing that obtaining millions of books needed for fair use training required the direct downloading, which ultimately serves the same transformative purpose.

Authors Push Back

The authors' legal team was quick to challenge Meta's late filing. In a letter to Judge Vince Chhabria, they accused Meta of using an "improper end-run around the discovery deadline." They noted that Meta had been aware of the uploading claims since November 2024 but never raised this fair use defense until now.

Meta's attorneys countered that the defense isn't new at all, pointing to the parties' joint December 2025 case management statement where it had explicitly flagged the defense. They argued that the authors' own attorney had addressed it at a court hearing days later.

The Authors' Own Words Backfire

In a twist that may strengthen Meta's position, the company's interrogatory response cites deposition testimony from the authors themselves. Every named author has admitted they are unaware of any Meta model output that replicates content from their books.

When asked whether it mattered if Meta's models never output language from her book, Sarah Silverman testified that "It doesn't matter at all."

Meta argues these admissions undermine any theory of market harm. If the authors cannot point to infringing output or lost sales, the lawsuit becomes more about challenging the training process itself—which the court already ruled was fair use.

National Security Implications

Meta added another dimension to its defense by stressing that its investment in AI has helped establish U.S. global leadership in artificial intelligence, putting the country ahead of geopolitical competitors. This framing suggests that allowing such training methods could be crucial for maintaining American technological supremacy.

What's at Stake

Judge Chhabria's decision on whether to allow this "fair use by technical necessity" defense could have far-reaching implications. The outcome will be vital not just for this case but for many other AI lawsuits where the use of shadow libraries is at stake.

The BitTorrent distribution claims remain the last live piece of a lawsuit filed in 2023. As the legal battle continues, the tech industry watches closely to see whether Meta's novel defense will reshape how copyright law applies to AI training in the digital age.

For now, the question remains: can technical necessity transform what would otherwise be copyright infringement into fair use? The answer could determine the future of AI development and the boundaries of copyright protection in the digital era.