A January 2008 Arbitron-Edison Media Research study found that an estimated 33 million Americans had listened to online radio in the past week.
This represents 13% of the US population ages 12 and older, and is an increase over the previous year when 11% of the population (29 million) had listened to online radio in the past week.
Podcasting use is also rising and now reaches 18% of the US population, up from 13% a year ago. An estimated 23 million, or 9% of Americans had listened to a podcast in the past month.
"Traditional radio and Internet-only radio must realize that they are now part of an even broader world of online information and entertainment options and respond accordingly," said Pierre Bouvard, president of sales and marketing at Arbitron.
"Advertisers who want to go where the trends are pointing need to be more involved with the new forms of audio media as they continue to expand," Mr. Bouvard said.