netflix is already doing that. if you haven't tried one of their interactive movies try it out. you'll quickly realize that it sucks dog and tv is much better when you're being told a carefully crafted story instead of pausing the show every few minutes to ask the viewer what they'd like to see.That's not quite what I have in mind. The kind of thing I'm thinking of is still decades away.
If you hadn't noticed, this is Forum 2.0