Podcasting is a
method of publishing audio programs via the Internet, allowing users to
subscribe to a feed of new files (usually MP3s). It became popular in late
2004, largely due to automatic downloading of audio onto portable players
or personal computers. Podcasting is distinct from other types of online
media delivery because of its subscription model, which uses a feed (such
as RSS or Atom) to deliver an enclosed file. Podcasting
enables independent producers to create self-published, syndicated "radio
shows," and gives broadcast radio programs a new distribution method.
Listeners may subscribe to feeds using "podcatching" software (a type of
aggregator), which periodically checks for and downloads new content
automatically. Most podcatching software enables the user to copy podcast
to portable music players. Any digital audio player or computer with
audio-playing software can play podcasts. From the earliest RSS-enclosure
tests, feeds have been used to deliver video files as well as audio. By
2005 some aggregators and mobile devices could receive and play video, but
the "podcast" name remained most associated with audio.
"Podcasting" is a portmanteau word that combines the words "broadcasting"
and "iPod." The term can be misleading since neither podcasting nor
listening to podcast requires an iPod or any portable player. Aware of
that misleading association from the beginning, some writers have
suggested alternative names or reinterpretations of the letters "p-o-d",
without winning much of a following. Another little-used alternative is "blogcasting",
which implies content based on, or similar in format to, blogs.