Recently I've seen both business and political leaders here in Michigan put an audio or video file onto a web page and claim they have a podcast.
Unfortunately, this further confuses the general public as to what makes something a podcast. Claiming a media file on a web page is a podcast would be like writing a single article, making copies you put on your front porch, telling people they could stop by to pick it up, and then saying you are publishing a newspaper.
A podcast is episodic, like a television series with many shows delivered at regular intervals, e.g. once a week. In addition, like a magazine or a newspaper, you subscribe (usually free). With a magazine subscription, you don't have to go back to the newsstand every week or month, looking to see if a new issue is available and then decide to purchase it. The magazine just keeps showing up at your door with no additional effort on your part.
Podcasting is a tool of great value for doing business in The Long Tail. Unlike radio, there is no limit to the size or number of programs in podcasting. The key of course is how to reach your audience and not get lost in the thousands of podcasts that are getting launched on a regular basis. This is where branding, search engine optimization and knowing how to connect with your audience comes into play.
Pull vs. Push
This distinction between a podcast and simply putting media on a web page, is significant in terms of Pull vs. Push marketing. For example, in the old business model for music, radio stations could push songs and create hits, simply by playing a song over and over again. But, now people are able to select what they want and listen to it when they want it by subscribing to podcasts. Newspapers, TV and radio are push media. A podcast is pull media, because users select what they want and subscribe to it.
The act of subscribing is significant because users who choose to subscribe are implicitly gving you permission to keep providing them with new episodes, which then arrive automatically, without additional effort on the part of the subscriber. There is great power in this, as these people are likely to be real fans and building a community around these fans is more likely to increase concert attendance and even lead to things like merchandise sales. Getting to know your fans better by providing them ways to interact means you would be less likely to offer them something they do no want, and it makes it easier to keep things real. Thus, what might be advertising in a push medium, can really be considered a service people want in a pull medium.
Syndication
Done properly a Podcast can be like a syndicated newspaper column that appears in different newspapers all over the world. A Podcast is a media file (audio or video) inside an enclosure. RSS stands for really simple syndication.
The most popular way people currently get a Podcast is by using iTunes to subscribe to an RSS feed, but RSS is a standard and the future (or even the present for some) may hold all sorts of interesting alternatives to iTunes. In addition, iTunes itself will continue to evolve.