Switching from analog to digital let broadcasters offer higher picture definition, because a digital signal can be compressed far more than an analog signal. Compression allows stations to fit more information in the signal. That means you're getting a clearer image with digital television than you would from an analog signal. In fact, even though digital signals get weaker with distance, just as analog signals do, digital signals won't degrade in quality. As long as you have a signal, you'll get a clear picture [source: Cringely].
There's another advantage of having additional bandwidth available. Using digital broadcasting, local stations are able to offer more programming to their viewers than they could with an analog signal. How? Multicasting, or broadcasting several shows within a single frequency. Many stations across the United States are already multicasting. For example, WRAL in Raleigh, N.C., broadcasts a 24-hour news feed alongside its regular programming [source: USA Today].
If you have a digital-to-analog converter box and a terrestrial antenna, you can take advantage of your local station's multicasting, if they offer it. Cable and satellite providers may not necessarily add the additional stations to their lineups, however, so you may not see them if you subscribe.
If you still need a converter box, you may still be able to get a $40 coupon from the U.S. government at dtv2009.gov, if there are any still available. You could also buy a new television with a digital tuner, if that's what you would prefer, though that's a more expensive option.