Podcasting became popular back in 2004 as a method of publishing sound files to the Internet, allowing users to subscribe to a feed and receive new audio files automatically. Podcasting is distinct from other types of audio content delivery because of its subscription model, which uses the RSS 2.0 file format. This technique has enabled independent producers to create self-published, syndicated "radio" shows, and has given broadcast radio programs a new distribution channel.

Differences from traditional broadcasting
Unlike radio programs, which are generally listened to as they are broadcast, podcasts are transferred to the listener as a digital media file and are consumed at the listener's convenience, similar to a VCR playing back a pre-recorded TV show.

From the producer's perspective, podcasts cannot have live participation or immediately reach large audiences as quickly as radio can. However, podcasting allows individuals to easily transmit content worldwide without the need for expensive equipment or licenses, and is frequently used together with an online interactive bulletin board or blog.