Like so many other emerging Internet technologies, podcasting is simultaneously new and old hat. It is still new in that hardly anyone had heard of the concept as little as two years ago. But it is old in that it has been hard to not run into some story on the blogosphere or in the popular press where podcasting hasn't been a topic.
Here are just a few examples of what I mean:
The University of Michigan's school of dentistry is using podcasts as supplements to their lectures; according to an article that ran in the Ann Arbor News (which I blogged about), the dean of the school is a big fan of the iPod.
The Chronicle of Higher Education dubbed this practice as Coursecasting and suggested that already faculty were split on its role in college classrooms. There have also been a number of popular press articles suggesting coursecasts of classroom lectures are causing a decrease in class attendance.
I think you get the idea. What's missing from many of these stories about podcasting is any clear definition of what a podcast actually is, and what the difference is between a podcast and a run-of-the-mill audio file. The differences between a simple audio file and a podcast are subtle, but for my purposes here, I think the differences do matter.
By "audio file," I mean a sound recording available on the Internet and suitable for downloading and listening. In other words, this link to a simple audio file is an example of what I'm talking about, and the audio file that introduces this site is an example. There are a variety of different formats for audio files, though the two most common are .wav and .mp3. This particular audio file is not an example of "streaming media," which requires you to be connected to the Internet and to use software like RealPlayer. Rather, this file is published so users can download it, meaning that you could download the file, disconnect from the Internet, and still listen to it. In fact, you could even listen to this file on a portable device like an iPod if you manually installed it.
"Podcasts" have many of these characteristics. According to this entry at the Podcasting News web site, the Oxford English Dictionary defines podcast as "a digital recording of a radio broadcast or similar programme, made available on the Internet for downloading to a personal audio player." In other words, podcasts are also (or at least can be) simple audio files.
However, despite the authority of the source, I don't think this definition is completely accurate. First, despite the obvious connection between the words "podcast" and "iPod," you don't need an iPod or any other personal audio player to listen to a podcast; rather, you can listen to a podcast with just a computer and appropriate software.
Second, podcasting is increasingly about more than simple audio or "similar programmes." As I discuss in the "What I Learned and What I Continue to Learn" section, more and more podcasts are being enhanced with images and video.
Third and most important for my definition and discussion here, podcasts are distinct from other media files published on the Internet in that they are enabled with a syndication technology that allows users to automatically receive updates. In other words, once a user subscribes to a podcast, the user receives updates of that podcast on their computer.
The traditional world of print offers a useful analogy: a simple audio file posted on the Internet (or any other media file, for that matter) is like the magazine rack at the store: in order to get this content, you need to go to the store, pick out your magazine, and then return home to read it. A podcast (or any other media "delivered" via a syndication technology) is like subscribing to a particular magazine and having it delivered directly to your house: you check your mailbox and there's your magazine ready for reading. iTunes and similar software works the same way: once you subscribe to a podcast with iTunes, you receive newly updated podcast files delivered to your computer every time you launch the iTunes software.
I discuss and explain this in more detail in the section titled "Podcasting, 'On the Cheap,' and beyond."