Dumb fucking move.
Didn't these people learn from the music industry that free downloads and samples on unofficial sites leads to greater sales, not fewer.
With Viacom's properties, the person watching a snippet from one of their shows on YouTube is probably already a fan. Being able to share something he thought was really funny with his friends increases his loyalty to the show. And may even get his friend, who's never watched it, to tune in.
So now all they've succeeded in doing is pissing off the fans who relied on YouTube downloads and made themselves look like the teacher who takes the ball away.
Now the press reports that they were looking to set up their own YouTube-like site, but that's even dumber-- the whole point of YouTube is the authenticity-- the fact that what's up there is random, not corporate. Not to mention the ease of being able to go to one site for all your download needs.
The internet is not going to kill television. It's just going to change the way people interact with it in that it gives them a way to actually interact with it. There are sites with plot summaries, message boards, character histories, video clips to let you interact with any vaguely popular show. I can't tell you how many times I've checked one of these sites out (even the official ones) to get someone else's take on an episode, to catch up on one I missed or to otherwise get on board. It's the pop culture equivalent of reading a book of literary criticism about your favorite author.
And rather than killing television, it just makes people's loyalty to TV that much stronger.