A Federal court ruling on a copyright case from the early days of YouTube could have a sweeping impact on how media companies police online video. And it could give a boost to Facebook, which is just starting to navigate the video copyright waters that Google has traversed for years.

In 2007, Stephanie Lenz uploaded a 30-second video of her toddler bouncing to Prince’s “Let’s Go Crazy” on YouTube. Universal Music Group, which owned the copyright to Prince’s song, sent YouTube a takedown notice. Lenz sued, claiming the notice violated the Digital Millennium Copyright Act, which protects certain types of fair use, beginning a lengthy legal battle that became known as the “dancing baby case.”

On Monday, the Ninth Circuit of the U.S. Court of Appeals sided with Lenz. The court ruled that copyright owners must consider the fair use clause before they issue takedown notices to YouTube and other digital media hosts, which Universal failed to do. “To be clear,” the ruling states, “if a copyright holder ignores or neglects our unequivocal holding that it must consider fair use before sending a takedown notification, it is liable for damages …”

The Electronic Frontier Foundation, a legal advocacy group, filed the suit on behalf of Lenz. “Today’s ruling sends a strong message that copyright law does not authorize thoughtless censorship of lawful speech,” Corynne McSherry, the EFF legal director, said in a statement.

The ruling also sends a message to tech companies that host uploaded content. Since 2006, Google has relied on its “Content ID” system for rights holders to flag DMCA takedown requests. Twitter has taken a more passive approach. So has Facebook, which says that it is building out its own system, but clearly benefits from letting videos proliferate on its site — many of which media companies like Universal would prefer to have pulled.

Google and Facebook both declined to comment. In 2013, Google, along with Twitter and Tumblr, filed an amicus brief in the case in support of Lenz. Representatives from Universal did not immediately respond to requests for comment.

Here is Lenz’s dancing baby.

Update: The Recording Industry Association of America (Universal is a member) sent over this statement, courtesy of its executive VP Jonathan Lamy: “We respectfully disagree with the court’s conclusion about the DMCA and the burden the court places upon copyright holders before sending takedown notices. But we are pleased that the Ninth Circuit made it clear that a court may not second guess a copyright owner’s good faith belief that the fair use does not excuse infringing conduct.”