After years of litigation, and a complete defeat in a New York district court, Viacom’s lawsuit against YouTube is back before the Second Circuit Court of Appeals. You’d think by now that Viacom, having lost battle after battle in this war against a version of YouTube that even Viacom admits hasn’t existed since 2008 (when YouTube launched its Content I.D. filtering program), would wise up and walk away. You’d be wrong.

Admittedly, there’s a fair amount of money at stake. Thanks to copyright’s irrational statutory damages provisions, even a partial win can mean a windfall for Viacom. But that’s not what this case is about. Instead, it's an effort by Viacom and its friends at the MPAA and the RIAA to get the courts to undermine the safe harbors of the Digital Millennium Copyright Act (DMCA).

A particularly dangerous piece of Viacom’s latest argument is its suggestion that YouTube "induced" infringement and, therefore, effectively loses the safe harbors. As we explain in an amicus brief filed today, Viacom gets it wrong in at least two ways.

First, “inducement” is just a particular species of secondary copyright infringement, and the DMCA safe harbor expressly provides protection for all types of secondary liability. Therefore, if a service provider has otherwise followed the DMCA rules (taking down material when its get s a proper DMCA notice, etc.) a content owner can’t use inducement to effectively strip a service provider of DMCA protections.

Second, Viacom gets the standard for inducement liability wrong, setting the bar much too low. According to Viacom, a bunch of, ahem, ill-advised internal emails, knowledge that the service could be used to infringe, and the business choice not to let some content owners use its filtering tools, taken together, amount to inducement.

Fortunately for the millions of users who rely on new and innovative services like YouTube, that is not enough. That’s because copyright inducement is not a ‘thought tort’ and because the bar against a finding of inducement is set particularly high where the service has substantial non-infringing uses. As we explain in our brief, Viacom has to show affirmative and public acts encouraging infringement, and link those acts to actual infringing activity.

The legal point may be a bit obscure for non-lawyers, but the stakes shouldn’t be. It seems likely that YouTube will win this battle. The company has done a good job of showing that it offers a basic and valuable service that is used for any number of lawful purposes, and has since the beginning. It’s also clear the YouTube has gone well beyond its DMCA obligations in policing infringement. We expect the Second Circuit, like the district court, will send Viacom packing. But we are worried about the many new platforms and services being developed right now by innovators who don't happen to have a lawyer monitoring their every communication and who are more interested in growing their business than making sure their services can’t be used to infringe copyright. Those innovators need to know that a few embarrassing emails won’t be enough to destroy their business.

That’s why we are urging the court not to endorse Viacom’s interpretation of inducement and the DMCA. Here’s hoping the court gets it right.