Comes from the Latin 'Podi Castae'
which literally meant 'Cast (upon my) audio-device'
In recent years this has used by people in the form Podcast, especially because of a leading audio player called the iPod.
Podcasts are programmes (audio or video) that are hosted (usually) on the Internet, where they can be downloaded On-Demand as audiences desire
Since their release, The Ricky Gervais Show Podcasts have continually been top of the charts.
Largely due to The Genius of Karl Pilkington.