Glen Beck’s announcement this week that this September he’s adding online subscription-only video network to his media empire, made cable networks and paid content folks take notice. If anyone can make such a bold move, it might be Beck, who already has over 80,000 subscribers to his site GlennBeck.com.GBTV will cost $4.95 per month to access Beck’s show and $9.95 a month to subscribe to all of the site’s programming.The cable networks (like Fox, which Beck just left) are surely anxious that Beck’s endeavor will succeed all too well, bringing eyeballs away from cable TV and encouraging other cable stars to migrate the online, subscription-only model.Those of us in the world of paid content can’t wait to see how it plays out and how it could serve as the model for many other big names to get into the subscription content business.The big question remains whether Beck’s audience is ready to adapt their viewing habits? The New York Times sums it up well: “The business decision by Mr. Beck’s company, Mercury Radio Arts, hinges on an expectation that more and more people will figure out how to view online shows on their TV sets through set-top boxes and video game consoles – and that they will subscribe directly to their favorite brands.”Beck is certainly on to something since such a site requires a huge, established following. Hey, Oprah Winfrey, are you listening? You might just be the next big name behind a star-powered paywall site…