The TV world is going digital, as bit by bit digital technology replaces the old established analog TV technologies and devices. While the relatively younger computer industry was digital from the start, consumer electronics like TVs have a wider and older history and started out purely analog. This had not changed much until recently, with almost all modern households still equipped with "old-tech" analog audio and TV devices.
The switch to new digital consumer technologies has been in progress for a long while now, but it is taking its sweet time. A good example is the compact disc - it took a long time until the audio CD finally replaced the vinyl record. A similar story is the adoption of the DVD to replace the old analog VHS video system.
Finding a widely accepted technology standard is the biggest barrier when adopting a new digital system to replace an old analog technology. The big names of the industry try to unite with others in consortiums to define new standards, but that's not always an easy task. Some companies may favor differing solutions, and the result is two or more standards competing in the market. This often results in high prices for the devices, incompatibilities between the different standards, and confused consumers. The situation usually does not change until one standard wins this fight after a few years. And it's not always the best technology that wins, but the one that makes the most sense for the consumer. That's the situation we're facing now with digital TV.