Where we lived Warner Cable was testing the "new" interactive cable system called 'Qube'. They had interactive game shows, and would hold impromptu contests while you were watching specialized content.
None of this was on demand, you had to wait for them to activate your console during the show(s) so you could respond. My brother and I watched one of the first Concerts on cable (The Rolling Stones during the Tattoo You tour). We even won a free copy of the LP (They gave away about 100 or so, I think).
This was in the Seventies, in Columbus, OH. Fun times, but Warner eventually determined that it was not worth the effort (even though most Cable/Satellite remotes STILL have interactive buttons), and to this day, even DirecTV has only limited interactive capabilities, and is limited to mainly ordering content, and on demand movies, although you can bring up your local weather on DirecTV.
In short, Interactive TV will NEVER take off. If I wanted to get on the 'Net, I'll grab my laptop while watching whatever show is on (That's what we do now, on the VERY rare occasions where we want info NOW, Mainly limited to ordering things off of QVC - Well, she makes me order HER stuff . . .
). 
