Podcasts and Podcasting – What is it?

Perhaps by now you've heard of podcasts. Perhaps not. Either way, it appears that podcasting is part of the leading edge of the “Web 2.0” phenomenon of new tech companies and new media. But exactly what are they?

The term “podcast” usually refers to an audio “show” that people subscribe to and download via the Internet. One way to think of podcasts is as online radio shows, that are not live but are downloaded “on demand” when the user checks to see if there are new shows. There are podcasts of varying quality for just about every topic one can imagine.

Most podcast listeners subscribe to multiple shows, and listen to them via their personal mp3 players while in the car, commuting to work, exercising etc. Others listen to their podcasts while at work at their computer. Either way, the shows appeal to their users because they are often focused on niche interests that appeal to the listener – such as hobbies, or other interests. They are also usually free.

How Does It Work?
Most users find podcasts either through word of mouth, or via Apple's iTunes music store. There are also many websites that have directories of podcasts, and some users find podcasts by using their favorite search engine. Regardless of how they get it, the key element of a podcast is its “feed.” This is an RSS XML file that basically controls what audio files are distributed to the users. By subscribing to this feed using a podcasting client or “podcatcher”, the user is notified when new episodes or shows are available for that podcast. The most popular client right now is Apple's iTunes software, which allows users to easily subscribe to podcasts and transfer new shows to their ipod mp3 player – but there are many other pieces of software that fulfill this function.

The podcast itself is typically an audio file – generally either in mp3 format or sometimes in Apple's AAC format – but it can be any sort of file. There are “vidcasts” which distribute video instead of audio files. Regardless of the file type, the mechanics are the same. The podcaster uploads the file to some sort of website, and then add the new episode to their feed. At that point, the next time a subscriber checks their subscription, they will be able to download the new show.

There's no easy way to determine just how many podcasts or podcast listeners there are out there. At this point podcasting is about a year and a half old, and showing constant growth. Popular podcasts such as This Week in Tech and Diggnation have claimed to have as many as 300,000 subscribers – but due to the nature of how podcasts work, there's no good way to know exactly how many listeners a given podcast has. But there's little doubt that the numbers are growing quickly, especially since Apple added Podcast capabilities to iTunes in mid 2005. There's every reason to believe that 2006 will be a year in which podcasting will move ever farther into the mainstream, becoming a useful tool for organizations and users alike.