TargetSpot says its new study shows Internet radio listeners "are more tolerant of digital audio ads than broadcast AM/FM audiences." Parks Associates conducted the study, "Attitudes Towards Digital Audio Advertising," for TargetSpot (which is a digital audio ad network). You can download a summary of the study here.
The study found even when it came to ads that Internet radio listeners didn't find interesting or important, "they are more accepting of them and less likely to stop listening than are listeners to traditional Broadcast AM/FM Radio." TargetSpot also says its study shows most Net radio "listeners don’t mind ads if they perceive they will receive something of interest in return," mobile listeners are "amenable to receiving ads," and they're mostly fine with targeted advertising.
The study summary is here.