DTV has been around since they 1995-ish range. So... any issues regarding the switch must have already been resolved. They just don't want to pay for the extra broadcasting range to reach rural areas. Also, yes I relize a large number of you must watch a lot of online TV like I do myself, but there are times when a TV is just unbeatable. For one reason, you get the raw broadcasts. I want to watch the new Eddie Izzard skit as soon as its on TV, not wait a week for it to pop up on the web xP

Digital signals are more resistant to disruption, noise and interference than analog signals, because there's room for error - screwing up the waveform even slightly for analog signals destroys information - it's just that you still get the picture, maybe with ghosting or some weird colour or a bit of fuzz or something, but it's still impaired.

When it's digital, even before you get into the world of error-correcting codes and the like, you need to change the signal enough to turn a 1 into a 0, or vice-versa - which requires more disruption.

Think of it like this - an analog signal (i.e., old TV) sends the intensity that the TVs cathode ray tube should emit at for each position it's in. It directly encodes the picture in a format with no room for error loss - if you even slightly distort the analog signal, it changes the picture - a common one you may have seen is 'ghost' images of whatever's going on - those are caused by the signal reflecting off of something and being picked up later.

Digital signals have room for loss - you can distort the signal a bit without changing the picture.