Meta is facing a class-action lawsuit from authors over the use of pirated books for training its Llama language model, arguing that the distribution of these books via BitTorrent constitutes fair use. The company used shadow libraries like Anna's Archive to gather text, and a California court has partially ruled that using pirated books for training large language models falls under fair use, although the issue of copyright infringement related to downloading and distribution via BitTorrent remains unresolved. The plaintiffs claim Meta has not previously indicated a fair use defense regarding file-sharing, while Meta asserts that authors have not shown evidence of their works being reproduced by the Llama model. The judge will ultimately decide on the admissibility of Meta's defense.