boingboing suggests that HDTV will flop and looks admiringly at the UK's Freeview system.
Cory Doctorow overstates the case slightly:
1. Freeview is "standard definition", but it is standard definition PAL, which is higher definition than the US and Canada's NTSC. On paper the difference isn't that huge, but subjectively to me it's a very significant one - NTSC looks as much worse than normal as HDTV is better. Thus there is likely to be a bigger push for HDTV in NTSC countries than PAL ones.
2. Freeview exists by accident, as the original infrastructure was built as a subscription service by ITV Digital, which then went bust. Left with the infrastructure and proof that people weren't willing to pay subscriptions for it, converting it to a free service made sense.
3. Freeview's terrestrial broadcast signals don't have 100% coverage - some remote areas are not covered. By British standards, probably 20% of the US population live in remote areas - the UK is smaller than Oregon.
Significant update: Further to point 3, I recently tried to pick up Freeview myself, as an alternative to my subscription-based cable service. What I found is that Luton is basically not covered. Luton is a town of 200,000 people, 35 miles or 30 minutes from central London, and I can't pick up a signal. Asking around, quite a few people have tried, and given up and got cable or satellite. If I spend the equivalent of two years' cable subscription on installing an antenna on a tall pole on top of the house, there is a chance I might be able to get a decent signal -- but only a chance; there are two hills directly between the town and the nearest transmitter 22 miles away.