"Arbitron/Edison study chills the already thin air of HD Radio"

"All you need to know about this research is this: It says relatively
few know about HD. It says that number hasn't gone up. And it implies
that folks are aware of what they care about, not vice versa. It also
strongly suggests this isn't going to change any time soon - as in,
forever."

http://www.hear2.com/2008/04/arbitronedison.html