Digital audio formats, like satellite radio, online radio, and podcasting — subscription-based programming that is pushed to MP3 players — are creating new business models and opportunities in radio and the music industry. According to "The Future Of Digital Audio," a new report from Forrester Research, Inc. (Nasdaq: FORR), 20.1 million US households will listen to satellite radio, and 12.3 million US households will use their MP3 players to listen to audio podcasts by the end of the decade.