25. Syndication and Podcasting
When you make changes to your site, it's nice to have people notice. Although mass emailings might do the trick, they also might alienate your visitors. Instead, you can publish a summary of recent changes or feed of your site, in a format that can be read by specialized programs called aggregators. If your visitors decide to subscribe to your feed, the aggregator automatically notifies them of any updates to your site. The visitors can then either view the change right in the aggregator window, or jump back to your site to read it in situ. This process is called syndication. One of its strong points is that it gives control to your visitorsthey choose whether or not to subscribeas it gives them access to your updated content.
In the early days, it was only text articles that were syndicated. Since 2004, however, with the advent of enclosures, you can create multimedia feeds called podcasts. Podcasts make audio, video, still image, or even PDF files available to your subscribers, sometimes with no affiliated Web site at all. They're not necessarily designed for iPods, despite their name, though iPods can make them mobile. Apple has helped make podcasts popular by making them freely available through its iTunes Music Store, which serves as a podcast aggregator, or podcatcher.
In this chapter, I'll show you how to decide what to include in a feed for your Web site, how to write the actual feed, how to publish the feed, and how to subscribe to the feed.