Presumably they're getting a ROI, though. They're obviously tracking the results, since the ads always tell listeners to go to a particular URL to get a discou

Presumably they're getting a ROI, though. They're obviously tracking the results, since the ads always tell listeners to go to a particular URL to get a discount. If they're getting a ROI it means that this form of media is working as an advertising medium. That seems like a good judge of health to me.