impressedWebcast networks are defined as radio station owners that stream their content online or companies that aggregate online audio programming. Webcast networks are ranked according to their total monthly aggregate tuning hours (ATH) - the total sum of hours that listeners tune to a given station.
Live365 - an Internet radio provider that enables consumers, terrestrial radio stations and organizations to create their own radio stations or listen to thousands of stations created by others - was listened to for almost five million ATH. RadioWave ranked second with 900,200 ATH. Moving into the top five, Public Interactive ranked third with 759,200 ATH.
SOURCE: http://www.arbitron.com/webcast_ratings/home.htm
