Interactive television represents a continuum from low interactivity (TV on/off, volume, changing channels) to moderate interactivity (simple movies on demand without player controls) and high interactivity in which, for example, an audience member affects the program being watched. The most obvious example of this would be any kind of real-time voting on the screen, in which audience votes create decisions that are reflected in how the show continues.
A return path to the program provider is not necessary to have an interactive program experience. Once a movie is downloaded for example, controls may all be local. The link was needed to download the program, but texts and software which can be executed locally at the set-top box or IRD (Integrated receiver/decoder) may occur automatically, once the viewer enters the channel.
The first interactive television system was launched in the late 1970s by Warner Cable. It was a two-way interactive cable system called QUBE in Columbus, Ohio. It was not rolled out beyond Ohio. Since then a number of services for creating interactive applications have come and gone. These included Time Warner’s Full Service Network in the early 1990s, WebTV, and AOLTV, in the late 1990s.