A podcast is a digital media file, or a series of such files, that is distributed over the Internet using syndication feeds for playback on portable media players and personal computers. A podcast is a specific type of webcast which, like 'radio', can mean either the content itself or the method by which it is syndicated; the latter is also termed podcasting. The host or author of a podcast is often called a podcaster. The term "podcast" is a portmanteau of the name of Apple's portable music player, the iPod, and broadcast; a "pod" refers to a container of some sort, and "cast" to the idea of broadcasting.
In other words, a podcast is a collection of files (usually audio and video) residing at a unique web feed address. People can "subscribe" to this feed by submitting the feed address to an aggregator (like iTunes - software that runs on the consumer's computer). When new "episodes" become available in the podcast they will be automatically downloaded to that user's computer. Unlike radio or streaming content on the web, podcasts are not real-time. The material is pre-recorded and users can check out the material at their leisure, offline.
Though podcasters' web sites may also offer direct download or streaming of their content, a podcast is distinguished from other digital media formats by its ability to be syndicated, subscribed to, and downloaded automatically, using an aggregator or feed reader capable of reading feed formats such as RSS or Atom.
Certain podcasts, like those using technology developed by TalkShoe, can even be live and interactive. Dozens of podcast enthusiasts can be on at once, with the TalkShoe "host" being able to control their audience in the same way a radio host can.