I wrote this article a few weeks ago, but it wasn't ever published. I thought that it might make a good addition to Biz Podcasting.
The term podcasting refers to the production and distribution of podcasts. Podcasts are essentially Internet radio shows that are made available as pre-recorded shows.
The term podcast originally referred strictly to audio recordings which are roughly analogous to radio. Now, however, the definition has expanded to include virtually any form of media. While the boundaries of the definition of podcasting have been blurred, there remains one test. What differentiates a podcast from any other form of media is that a podcast is available via an RSS feed. Listeners and viewers can subscribe to that feed with a podcatcher.
The word podcast appeared in the Oxford English Dictionary in 2005 and is therefore now a genuine word. The word started life as a compound word composed of the words iPod and broadcast. Users do not require any form of digital media player to partake in podcasts, but in 2004 when the media was starting out, the Apple iPod was the most prolific digital audio player on the market, which drove the name.
The broadcasting part came from the realization that since broadband Internet is very common in large urban areas, there should be some way to listen to rich audio content 'on demand'. Audio files are still too large to instantly download to a computer as soon as the user clicks it, though, so the concept of subscription-based media was born. The idea is that listeners can subscribe to podcasts and their computers will check for new shows while users are otherwise occupied. Then, when the listener wants to hear to a show, he or she can simply click the already downloaded file and it will play. This system provides the illusion of broadcasted media on demand.
In general Adam Curry and Dave Winer are credited with creating the podcasting model, but there are many other people such as Tristan Lewis who have played major parts.
The true test of a podcast is whether it is available via an RSS feed, not the content or media form. A podcast feed is obligated only to contain some type of media, not a specific type. Therefore, pretty much any type of binary file can be delivered as a podcast.
While main stream media such as London's BBC radio is producing podcasts, most are created by amateurs with no professional experience or equipment. To that end, podcasters are constantly experimenting with different technologies and methods to produce shows. The list of podcast genres is growing daily and there is seemingly no end to the creativity of podcasters.