Video on demand is sometimes compared to an electronics video rental store. The user (customer) selects any one of a large number of available videos and takes it home to view. Only with video on demand the selection is made at home using the television set’s remote control, and the video starts immediately. A description of one real implementation can be found in (Nelson and Linton 1995). A more general treatment of interactive television is in (Hodge, 1995). Other relevant references are (Change et. al. 1994, Hodge et al. 1993, and Little and Venkatesh, 1994). Here we see a high-bandwidth (National or International) wide area backbone network at the center of the system. Connected to it are thousands of local distribution networks, such as cable TV or telephone company distribution systems. The local distribution systems reach into people’s houses, where they terminate in set-top boxes, which are in fact, powerful, specialized personal computers.