Podcast

Podcasting is a way 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 it uses the RSS 2.0 file format. This technique has enabled many producers to create self-published, syndicated radio shows.

Users subscribe to podcasts using "podcatching" software (also called "aggregator" software) which periodically checks for and downloads new content. It can then sync the content to the user's portable music player, hence the portmanteau of Apple's "iPod" and "broadcasting". Podcasting does not require an iPod; any digital audio player or computer with the appropriate software can play podcasts.

History

Origin of podcasting

By 2003, a number of blogs already published audio online, and the RSS file format was widely used for summarizing or syndicating content. Using RSS, former NPR host Christopher Lydon attached audio files to his weblog. Lydon's full-length interviews, which focused on blogging and coverage of the 2004 U.S. presidental campaigns, helped to inspire Adam Curry's iPodder script. Indeed, blogs would become an important factor in the popularization of podcasting.

Origin of the word

One of the first uses of the term "podcasting" was in an article in The Guardian [1] on February 12, 2004, though it didn't detail the RSS file format or automatic synchronization. In September of that year, Dannie Gregoire used the term to describe the automatic download and synchronization idea that Adam Curry had developed [2]. Gregoire had also registered multiple domain names associated with podcasting. That usage was discovered and reported on by Curry and Dave Slusher of the Evil Genius Chronicles website.

Unique attributes

Differences from traditional broadcasting

Unlike radio or streaming media, podcasts are time-shifted, meaning that listeners have control over when they hear the recording similar to a VCR playing back a pre-recorded TV show. Using a portable player, such as the iPod or a cell phone, podcasts are instantly available and can be listened to progressively while tending to other matters, therefore educating a busy listener at no time expense.

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.

Differences from other forms of online audio

Podcasting differs from broadcasting and webcasting in the way that content is transmitted. Instead of a central audio stream, listeners download audio files remotely and automatically. Podcasts can also include metadata such as dates, titles, and descriptions. Podcasting differs from autocasting in terms of content; podcasts are generally voice broadcasts while autocasting is a speech-synthesized version of regular text blogs. Audioblogs can be easily made into podcasts if they add support for RSS to facilitate automatic retrieval.

Other uses

Podcasting's initial appeal was to allow individuals to create their own "radio shows", but the system is increasingly used for other reasons, including:

• Radio stations podcasting their broadcasts, which apparently started in the U.S. on October 4, 2004 when Leo Laporte began re-broadcasting his KFI Los Angeles radio show as a podcast feed.

• In some instances, podcasts have been turned into unofficial audio tours of museums. New York Times article

See also

• List of radio stations with podcasts
• List of general podcasts
• Media RSS

External links

• What is Podcasting? at iPodder.org
• Podcasting VODcasting whitepaper at apple.com (PDF file)