This week, EFF asked a federal court in Florida to unseal records from the Disney v. Hotfile case describing Warner Brothers' system for sending takedown notices to websites. Warner, and the other plaintiffs in the case, want that information kept secret forever. But Congress is asking for input about the notice-and-takedown system created by the Digital Millennium Copyright Act, and a hearing is coming up soon. The Patent and Trademark Office is also holding public meetings on the DMCA. It'll be harder for the public to get involved in these conversations without knowing some basic information about how big copyright holders like Warner decide which files to target for takedowns. And copyright holders can't design their systems to comply with the law if basic parts of the court decisions that interpret the law are kept secret. That's why EFF asked the court to unseal these records.

Under the DMCA, copyright holders or their agents can send notices to Internet sites, declaring that some material posted by users infringes their copyright. The Internet site then has a legal incentive to take the material down, to avoid liability.(In practice, most sites respond to every DMCA notice by taking down the targeted content, even when the notices are improper.) Warner, like some other large media companies, uses some combination of web-crawling search robots and human review to find files that it claims are infringing its copyright, and then sending takedown notices to the sites that host the files.

Hotfile was a file-hosting site (a "cyberlocker") that was sued in 2011 by five major movie studios, including Warner Brothers. The studios claimed that Hotfile wasn't protected by the DMCA, and should be held responsible when Hotfile users posted infringing video files. Hotfile had set up a special Web interface for Warner to send takedown notices. Warner designed a system that apparently used robots to crawl through indexes of Hotfile content looking for movie files.

We don't know how Warner's robots work, or what they are programmed to look for. Warner claims it didn't entrust all of the copyright decisions to software, and there was some human review involved. But Hotfile accused Warner of using its system to take down files that merely had the same name as a Warner movie - even files that weren't video. And Hotfile also claimed that Warner was taking down copies of a free and open source program called JDownloader that Warner had no rights in, but simply didn't want the public to have. Judge Kathleen M. Williams looked at the evidence behind these accusations, and concluded that Warner might be liable under Section 512(f) of the DMCA. That section, which is also the basis of Stephanie Lenz's suit against Universal Music, prohibits copyright holders from sending takedowns without having a basis for believing that the material is infringing.

The court's decision meant that a jury could decide whether Warner was liable. But the parties settled on the eve of trial in November, and Hotfile shut down.

Judge Williams's decision was encouraging, but mysterious – we don’t get to see evidence of how Warner's system works and which of its improper DMCA takedown notices gave rise to liability. So we know that Warner may have crossed a line, but not how or why. Without seeing the facts that went into Judge WIlliams's decision, it doesn't help people design takedown systems that comply with the law, and it doesn't help anyone make informed arguments about the DMCA when Congress takes it up.

We can't do without informed debate. The House Judiciary Committee may hold a hearing on DMCA takedowns in early March. Lawmakers need to hear about how well the system is actually working, and whether it protects Internet users against having their speech curtailed by takedown-bots or overzealous and poorly trained reviewers. Actual data about major DMCA users like Warner is vital.

The courts are public institutions, and their proceedings should be open to the public as much as possible, according to our legal traditions and the First Amendment. We hope the Florida court will open its records on this this important issue.