Google TV, at least theoretically, conceptually erases the distinction between the web and television as a medium for video. It's all video, wherever it comes from. For broadcasters, that's scary! So ABC, CBS and NBC's websites are blocking Google TV.
If you go to one of their websites to try to watch a full-length show, like 30 Rock or Lost, you'll get a big ol' cockblock, just like you'd see if you try to go to Hulu with any other browser on a TV (see: the epic Boxee and Hulu battles). Fox, who's also part of Hulu, might block Google TV from its site too.
Here's the thing: Web advertising is worth a lot less than regular TV advertising. The ads for 30 Rock on Hulu or NBC.com dump a lot less change into NBC's pocket than the ones that run when 30 Rock airs on the network. So if you're watching broadcast content on your television, broadcasters want you to watch TV ads, not web ads.
That's the short version. The longer version is breaking down the conceptual barriers between media—where it doesn't matter where a video comes from, some indy producer on Vimeo or a giant studio—is a scary long-term prospect. These lines, between "quality" content produced in the old-school system and a really slick piece of viral video are important for Hollywood to maintain. So don't expect them to line up to help erase it. At least until there's a way to make sure they get paid. [WSJ]
Update: Google's trying to fix it.