Picking an RSS Format

Congratulations, you've decided to publish your own RSS feed! The first step is to decide which version of RSS you will use. You'll learn more about the inner workings of RSS and its various versions in the next chapter, but this overview of versions will help you start the RSS publishing process on the right foot.

There are three main versions of RSS as of this writing: 0.91, 1.0, and 2.0. According to www.syndic8.comthe huge RSS site that keeps all kinds of statistics on RSS and the many feeds out therethis is the percentage breakdown of RSS usage worldwide by version:

• RSS 0.91: 13 percent

• RSS 1.0: 17 percent

• RSS 2.0: 67 percent

• Less popular RSS versions: 3 percent

Besides RSS, there's Atom to consider, although it's currently less in use than RSS. How do you decide which version to work with? The next section examines the differences between these versions to help you choose.

RSS 0.91

RSS 0.91 is the simplest version. It's the easiest to work with, but it's also the most limited. Officially, it's been replaced by version 2.0, but it's still in widespread usage. It's easy to upgrade RSS 0.91 to version 2.0, and generally speaking, all RSS readers should be able to read version 0.91 (although that might not be true in the future).

This version has some restrictions; for example, you're limited to 15 news items per feed.

RSS 1.0

This version of RSS, which differs significantly from versions 0.91 and 2.0, is a bit of an offshoot: Based on the Resource Description Framework (RDF) language (which you can find out more about at www.w3.org/RDF), it's useful if you want to connect to RDF-based software. But in many ways, RSS 1.0 represents a branch of the main RSS tree.

RSS 2.0

The most common RSS version by far, RSS 2.0 may be your best choice as of this writing, if you want the most widespread audience. This version is an extension of version 0.92 (which was the successor to version 0.91). Versions 0.92 and 2.0 add powernotably, the ability to use enclosures, which is what makes podcasting possible. As you can see from the www.syndic8.com data above, RSS 2.0 is more widely used than versions 0.92 and 1.0 combined.

Note

You'll see more on the new features of RSS 2.0 in Chapter 4, "Creating RSS Feeds from Scratch."

Atom

One of the attractions of Atom is that it makes it easy to work with the data stored in the feed. The content of your feed is also easily filtered and organized.