What is interactive tv?

The simplest, Interactivity with a TV set is the one that is already very successful. This got its first big jump with the use of the remote control to enable channel surfing behaviors, and has evolved to include video-on-demand, VCR-like pause, rewind, and fast forward, and DVRs, commercial skipping and the like. It does not change any content or its inherent linearity, only how we control the viewing of that content. This is a kind of interactive TV, and not insignificant, but it is not what is meant in any full sense of the term.