Remember all the hype about virtual reality? Floods of breathless journalism assured us fantastic new computer-generated worlds were at hand which we could enter, simply by donning a headset plugged into a Mac or PC. It still hasn't happened.
Then there was the promise of HDTV - better television pictures viewed on a wide screen. The industry was abuzz. Then the heralds of change fell silent again.
Did the technology falter or were there other reasons? In the absorbing Technologies of Seeing, Brian Winston, director of the Centre For Journalism Studies at the University of Wales, argues that technological know-how is just the starting point. Innovation in the media is produced by many factors.
He asks: "How does technological change occur in mass communications?" The answer seems simple. A marriage of technology and economics. Surely when the technology is right and, when entrepreneurs sight fortunes to be made, they set about persuading us to pipe in cable or surf the Internet.
Winston argues that far more complex forces govern the process of innovation, sometimes speeding its development, at other times applying the brakes. He says: "Innovations are the creatures of society in a general sense. We are in the driving seat."
Take cinema's birth. Most of the technologies required had long existed and, if the social and cultural conditions had been right, the movies might have flickered into life earlier. Instead, other factors needed to create the social and cultural need for its birth - primarily industrialisation and its attendant demographics and, in their wake, a shift in public taste and the creation of a network of places of mass entertainment.
Winston also argues that new technologies are widely introduced only when it's clear they won't prove radically disruptive. His analysis of the gradual shift from 35mm to 16mm film stock as a medium is particularly fascinating. The long pre-eminence of 35mm film helped delay the creation of modern news and its concomitant challenges.
Cinema newsreel seldom covered news significantly. Cumbersome technology made it almost impossible and there was no economic or social demand. But then the need for an easy-to-use medium for military training in the Second World War arrived and was followed by the growth of television, 16mm film, cast for so long as the amateur relation to "real" film, gained acceptance for practical reasons. More mobile cameras with increasingly effective and sound recording helped create the modern news landscape.
So what will be the fate of virtual reality? Will it eventually arrive in the mainstream? Winston's arguments suggest that, once technological difficulties are solved, it might. Ultimately, it will be up to us - as a society - to arrive at a consensus where it is seen as a necessity.