Taken from: http://ipod.about.com/od/itunes/g/podcast_define.htm

“Podcast – A podcast is an audio or video program formatted to be played on the iPod and made available for free or for purchase over the Internet.

Podcasts are shows, similar to radio or TV shows, that are produced by professionals or amateurs and posted to the Internet for download and listening or viewing. Many podcasts are made available for free, though some must be purchased.

The name derives from the combination of broadcast and iPod.

Podcasts can be downloaded individually or subscribed to so that each new episode of the podcast is automatically downloaded to the subscriber’s computer. You can subscribe to a podcast at the iTunes Store or websites for the podcasts. Podcast subscriptions are usually facilitated using RSS”

Basically I view podcasts as being a more immersive radio show. Ihis I think is because the manner you consume it is more direct with it coming either through headphones or through a car’s stereo you feel as if you are in the show and apart of the conversation (or at least the best one do!).