Time Warner Cable announced this week that it has (finally) rolled out its interactive advertising system in NYC, and 2 big marketers are testing the waters: General Electric and General Motors (with American Express and Warner Brothers to follow).
Back in my Digitas days, I worked with a team at General Motors to launch the GM Virtual Showroom on the Time Warner, Comcast, and Cox cable networks. Research had shown that people were interested in viewing new vehicle information - especially hero shots of the car, interior/exterior features, and 360-degree spins - on the larger screens of their televisions (vs. their computer screens).
So we built a showroom which people could (still can) access on-demand with their television remotes, and we dreamed of the day when we could drive traffic to the showroom via a traditional :30 spot with a digital overlay that would tunnel through to the long-form video.
That latter part, while technically feasible, had not been fully operationalized by the MSOs (cable networks) at the time, so we used other means to drive traffic.
But now the dream has been fully realized, and I'm anxious to see how it all works out. I think the tv/computer convergence angle is going to be huge. People are getting much more comfortable interacting with the on-demand systems (although the programming guide interfaces leave much to be desired), and marketers are dabbling in direct response/fulfillment activities (e.g., opting-in to a program via the remote control, or requesting more information).
Digital cable set-top boxes contain your billing information, which means fulfillment - and targeting at the household level - is doable. It's only a matter of time until this takes off.