RSS, Links, and Metadata

by Bob DuCharme

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I've been thinking about how RSS item elements aren't quite links, but can be turned into links with very little trouble, such as conversion to HTML or loading into a news aggregator. Before then, they identify something to link to, but nothing to link from. It's up to the user of the RSS feed to put that linking information into a context that turns them into links.

And as linking information goes, I love RSS items, because each comes with a pack of metadata about its potential link destination, and the more that people can know about a link before traversing it, the more value that link has. While competing W3C Working Groups argued about whether link metadata should be stored in attributes, because that's what people are used to from HTML, or in subelements, because you can store so much more metadata, the growing success of RSS proved the latter camp to be correct. Inside of an RSS item element, you have one child element with a URL about a resource on the web and other child elements with metadata about that resource. The increasing use of the "dc:" prefix is another sign of progress that we shouldn't take for granted—more and more of this metadata actually conforms to a standard!

A recent weblog posting by Sean McGrath, who I've known since XML was a four-letter word, made an excellent suggestion about a source for even more metadata for links to weblogs. It's another indication of the excitement around RSS: the existence of this simple format for a new class of easily shared (meta!)data keeps inspiring new ideas for applications—especially linking applications.

Do you know of any new kinds of applications being built around RSS?