Apparently when Viacom issued their statement of 100,000 videos on youtube infringing their copyright, they didn’t really bother to look at many of them to verify that. There was a youtube video based on “Re: Your Brains”, a Jonathan Coulton song licensed under CC, that also got pulled:
Yeah, Viacom issued a massive takedown notice to YouTube, and a bunch of user-created content got caught in the crossfire. It seems like they just did a rough search on Viacom property names, and compiled the ENTIRE results into their takedown. So there was probably nothing in Spiff’s video that violated YouTube’s ToU, but some comment or tag that referenced a Viacom property to make it show up in the legal team’s search.
More details on the unfolding story on Jonathan’s blog.
It's always more complicated 