Among a Webmaster's biggest challenges are keeping content fresh and advertising what's new. The RSS specification for syndicating content is a way to meet both needs. Content providers create RSS versions of their news stories and register the RSS files with news aggregators. News aggregators, which can run on the Web (such as Moreover Technologies) or on your desktop (such as AmphetaDesk), regularly scan the RSS files at registered sites and display any new information. The aggregators get fresh content, and the content providers get click-throughs and backlinks to improve their search engine rankings.

RSS syndication was originally designed for newsfeeds, but it also can be used to broadcast event listings, software or book revisions, project updates, corporate news, and more. More recently, RSS feeds have become a popular means for bloggers to announce updates to their Weblogs.

Competing Specifications

What does RSS stand for? Depending on whom you ask, it could stand for RDF Site Summary, Rich Site Summary, or Really Simple Syndication. (RDF stands for Resource Description Framework.) The reason for the varying names is that RSS is not one specification. It is several competing specifications along two main lines: an RDF-based version that's powerful but complex and a non-RDF version that's simpler to use.

The dispute between the groups behind these specs is acrimonious, and neither shows any signs of backing down. Writers of aggregators don't have to take sides; they generally support both approaches. But content providers must make a choice. The dispute centers on how complicated and ugly RDF/XML really is and how important are the benefits it brings.

Both versions of RSS are based on XML. In fact, RSS is the most popular application of XML today. But the spec produced by the nonprofit RSS-DEV Working Group uses RDF/XML, while the commercial UserLand implementation sacrifices the advantages of RDF for a simpler syntax. The RDF-compliant spec is called RSS 1.0, and the non-RDF spec is called RSS 2.0—to the fury of the RSS 1.0 camp. But RSS 2.0 is not an improvement over 1.0—it's a completely different spec.

A third syndication specification, variously called Echo, Pie, or Atom, has recently garnered much attention. Atom's design goal is to combine the best aspects of the two RSS specs as well as resolve some of the difficulties in adapting a news syndication spec for use with blogs. Although it's too soon to know for sure, Atom may be the winner in the end.

Humans Versus Machines

RDF/XML is machine-readable, but it's not very readable for humans. How ugly is it? Opinions vary. People who know RDF/ XML well tend to think it's not so bad, but it doesn't make a good first impression.

Most people who use RDF/XML argue that human readability doesn't matter. Virtually no one hand-codes RSS. Bloggers use tools such as Radio UserLand and Moveable Type, and large companies use custom scripts designed for use with their content management systems. If humans don't write it or read it, does its ugliness really matter?

The UserLand camp says yes. They say that RDF compliance adds great complexity for little benefit. It's true that RSS 2.0 is easier to read and sufficient to create a news feed, but the spec is inelegant and limited, and information encoded using this spec can't be interpreted by RDF-aware applications.

RSS and the Semantic Web

RSS without RDF can be used for just one thing: news syndication. RSS with RDF opens the door to the Semantic Web, a developing technology for enabling machines to understand Web content so they can go out and do our bidding. RDF is a key component in the Semantic Web. XML by itself defines structure but not meaning; it makes information machine-readable but not machine-understandable. RDF/XML is a more constrained version of XML that encodes the meaning of information in a way that machines can interpret. (For more information on RDF and its role in the Semantic Web, see www.pcmag.com/article2/0,4149,31775,00.asp.)

Some aggregators (such as NewsMonster, with its built-in agent for bartering goods and services) are starting to take advantage of RDF capabilities. But unless use of the RDF-enabled spec becomes widespread, the universe of resources to work with will be small.

In the end, content providers will decide which spec will become the standard for syndication. If you're already using a non-RDF version of RSS, there's no pressing need to switch. But if you're looking at RSS for the first time, Version 1.0 is the better choice, it's likely to give you far more options in the future.