Podcasting is the preparation and distribution of audio files using RSS to the computers of subscribed users. These files may then be uploaded to digital music or multimedia players like the iPod. A podcast can be easily created from a digital audio file. The podcaster first saves the file as an MP3 and then uploads it to the Web site of a service provider. The MP3 file gets its own URL, which is inserted into an RSS XML document as an enclosure within an XML tag.
Once a podcast has been created, it can be registered with content aggregators, such as podcasting.net or ipodder.org, for inclusion in podcast directories. People can browse through the categories or subscribe to specific podcast RSS feeds which will download to their audio players automatically when they next connect. Although podcasts are generally audio files created for digital music players, the same technology can be used to prepare and transmit images, text, and video to any capable device.
Podcasting has been likened to TiVo because it allows users to listen to their selected podcasts whenever they like, similarly to the way time-shifting lets viewers watch television programs when it suits them. Furthermore, because of the portability of the player devices, users can listen to audio files from the Internet as they go about their daily activities - for example, listening to a news blog entry while at the gym, commuting, or just walking around.
Content producers are increasingly turning to podcasting as an inexpensive and user-friendly new distribution channel that has the potential to reach a large audience. Not surprisingly, musicians and bloggers are prevalent among the early adopters, but mainstream media organizations, including ZDNet and National Public Radio (NPR), are beginning to venture into podcasting as well.
The cultural milieu supporting podcasting is sometimes referred to as the podosphere, just as the cultural environment surrounding the blog is called the blogosphere.