This marked the start of rapid transmission of TV signals over wide areas. What we take for granted today-satellite television, cellular telephones, wireless and high-speed internet connections, and so forth-were part of science fiction only 40 years ago. Teenagers today are the first real citizens of the digital world. Unlike their parents, they have grown up in a world in which electronic delivery of information and entertainment is natural and more accepted than conventional forms like the newspaper, tape, or film.