37% of US internet users responding to a survey from The NPD Group said they listened to music on an internet radio service in the 3 months prior to the survey, according to a new report. That represents 27% year-over-year growth, and is good news for marketers, as research has shown these listeners to be highly receptive to advertising. But while the audiences for internet radio and on-demand listening (+18%, to 36%) are on the rise, the outlook isn’t good for CD sales. The number of consumers listening to music on CDs has plummeted by 16%. Read the rest at MarketingCharts.