Podcasting

Podcasting is the method of distributing multimedia files, such as audio or video programs, over the Internet using syndication feeds, for playback on portable media players and personal computers.

The term "podcast" is a portmanteau of the acronym "Pod" – standing for "Portable on Demand" – and "broadcast". (The name iPod was coined with Pod, prefixed with the "i" commonly used by Apple for its products and services.)

Thus podcasting refers to posting or transmitting an audio/ video file to be downloaded and viewed/heard by other internet users either on a computer or MP3 player. It involves making a multimedia file (usually in MP3 format) that is updated frequently available for automatic download, via an RSS feed, so users can listen to the file at their convenience.

A podcaster begins by making a file available on the Internet, usually by posting the file on a webserver. The content provider (podcaster) then announces the existence of that file in a feed (RSS or Atom).

A podcast-specific aggregator or podcatcher (software installed on the users' computer/ portable media player) checks each feed at a specified interval. If the feed data has changed from when it was previously checked, the podcatcher determines the location of the most recent item and automatically downloads it. The downloaded episodes can then be played, replayed, or archived as with any other computer file.

Podcasting's initial appeal was to allow individuals to distribute their own radio-style shows, but the system quickly became used in a wide variety of other ways, including distribution of school lessons, official and unofficial audio tours of museums, conference meeting alerts and updates, and by police departments to distribute public safety messages.