A podcast is an audio broadcast where the on-demand sound file is provided through web feeds. Thanks to the introduction of portable mp3 players such as the iPod, this form of broadcasting was quickly popular among radio amateurs. The term podcast is therefore a contraction of iPod and broadcast.
In 1997, Dave Winer described a way to include references to media files in RSS feeds. The method was then mainly used for web syndication. Podcasts became popular because of
(a) the breakthrough of broadband connections to consumers;
(b) the arrival of portable mp3 players with sufficient storage capacity and
(c) the advent of applications for listening to a portable media player or mobile phone.
The term podcasting first surfaced in 2004 when journalist Ben Hammersley described the new broadcasting technique. Dannie J. Gregoire adopted this term, after which Adam Curry popularized podcasting as something revolutionary.
For a podcast, the on-demand sound file is provided through web feeds. The webfeed contains a reference to the media file. An application that checks this file for changes and can be instructed to download new files automatically is called a podcast aggregator or podcatcher. Often this functionality is integrated into a media player such as iTunes. There are also podcast aggregators for smartphones. Some of these applications also offer their own guide with podcasts to which one can subscribe. There are also websites with a podcast guide.
For the distribution of copyrighted music there are legal rules, The provision of music may only be made available with the consent of the authors.
When the artist does not want to claim his music rights, the music is Podsafe. This corresponds to a Creative Commons license.
Podcasts gave radio amateurs a new platform with a wider reach. In 2005, podcasts created by hobbyists peaked. The emerging competition of professional radio makers – with public service broadcasting at the forefront – marginalises the number of active hobbyists.
The term podcast is also used for broadcasts or files with image (video podcast, compare VODcast), which are also suitable for listening only. In addition to the ability to stream or play the video and watch it, videos called podcast often include the ability to do so only with the audio on another website. Sometimes a podcast host gives a little explanation of what’s on display for the benefit of those who only listen to the podcast.