Wasn't this the very purpose of the DMCA safe-harbor provision? This seems like a slam-dunk for Google.
Viacom and other rights holders will likely play out the policy debate before Congress, arguing that DMCA should be amended to impose broader obligations on hosting parties (such as the obligation to remove whole categories of materials on request). Of course, Viacom will also argue on appeal that the DMCA already imposes such broader obligations (as they unsuccessfully argued to the trial judge here).
How would those categories be created if Google can't pro-actively scan content without running afoul of Safe Harbor's requirement that providers not vet material beforehand?
Am I misunderstanding something? Because it sounds like arguing for a "Category Take Down" is just a round-about way of arguing against Safe Harbor altogether.