Nice article from Canada on issues with digitial radio broadcasting.

Digital radio or digital audio broadcasting (DAB) has had a brief and troubled history. DAB was first developed with an eye to commercial use in the late 1980s. Via a digital radio technology called Eureka 147, broadcasters can transmit a complex signal with many potential applications, not the least of which is a crystal-clear sound. As CD-quality music plays, a radio display will show the song title and artist. Press a button and you can order the CD. Press another and you can order concert tickets. Stations can be personalized according to a listener's needs with the latest weather, traffic or stock market quotes available upon request...
While Europe's major broadcasters embraced Eureka 147, it was a very different story in the United States. Concern that a new dedicated digital band would undermine the value of FM stations prompted the United States to support a made-in-America compromise called IBOC (in band/on channel). The IBOC plan requires no new spectrum and squeezes new digital signals within the existing FM and AM radio bands. IBOC, recently rechristened HD Radio, was approved by the U.S. Federal Communications Commission in October and has the support of 14 of the country's top 20 radio broadcasters.
HD Radio has been met with much hostility by Canadian supporters of Eureka 147. They claim the U.S. plan will mean an inferior digital radio signal for the world's largest commercial audience.
"You're left with the conclusion why did they [U.S. broadcasters] bother? They ended up with a system that isn't particularly useful," says Steve Edwards, vice-president of corporate engineering and technology at Rogers Media, a unit of Toronto holding company Rogers Communications Inc.
More important, HD Radio has created a major stumbling block for the growth of Eureka 147. The two formats are not compatible and require separate digital receivers....
Supporters are quick to compare digital radio's slow birth to FM, a band that took about 30 years to capture the public's imagination.