An article by Mark Pilgrim in XML.Com states that "Really Simple Syndication is really only simple if you're doing it incorrectly," using the guid element as an example. That's a bogus claim to make about guid, a globally unique string that serves a simple purpose: Making sure that an RSS reader doesn't show the same item twice. Pilgrim's article provides a nice tutorial on how to normalize URLs for use as guid values, but he neglects to mention a salient fact: This solves a problem that no one is having. URLs ... read more

As a host containing thousands of weblogs, Weblogs.Com has to deal with one of the big scaling issues with syndication feeds: Once an aggregator subscribes to a feed, it could be checking the file multiple times a day, even when the site hasn't changed in years. For example, Java.Weblogs.Com hasn't been updated since 2001. A single user who subscribes to its RSS feed could be requesting that 13K file a dozen or more times a day. If the site has 20 subscribers, they could potentially be using 144 megabytes of ... read more

Using MySQL and PHP, I'm cobbling together a server-based RSS aggregator/publisher that makes it insanely fast to skim feeds, choosing items for publication without much descriptive text or editing. The code makes use of two terrific open source PHP projects: the Magpie RSS and Atom parser and Edd Dumbill's XML-RPC for PHP. Erik Thauvin uses this approach on Linkblog, checking a mind-boggling 1,600 feeds for technology and programming links and choosing the best 15-20 items each day. His site has quickly become a ... read more

Now that I've accomplished something tangible as a member of the RSS Advisory Board -- when the history books are written, let this serve as notice that Rogers Cadenhead authored the RSS 2.0 example file -- I think it's time to reveal my hidden agenda. I'm finding that I can't talk about RSS or Atom any more without arousing suspicion about my motives. I joined the RSS board for three reasons, not counting ego gratification: RSS 2.0 is a simple, successful format that I use all the time as a software ... read more

When I wrote a few months ago about a disclosure issue in The Guardian, I didn't expect that the complaint would still be rattling around on weblogs two months later. Perhaps I would feel more strongly if I were quoted in the piece, but to me it's simply a bad judgment call that should have been made differently at the time. I don't want to hang it around the writer's neck like an albatross. I am surprised that editors at The Guardian either don't feel like it was an error or won't admit it, but a lot of newspaper ... read more

I submitted a change to the Feed Validator documentation that was picked up by Sam Ruby this evening: a new answer to the question "How do I make Movable Type output valid RSS 2.0?" that includes a revised RSS 2.0 template. Some old RSS 0.91/2.0 templates in Movable Type produce invalid RSS because date values aren't correctly formatted. The new RSS 2.0 template in Movable Type 3.0 doesn't have this problem, but it includes a new date tag attribute, format_name="rfc822", that isn't supported in Movable Type ... read more

One of the distinct differences between RSS 2.0 and Atom Syndication Format 0.3 is the ability to declare the kind of information an Atom element holds. In an Atom feed, elements such as weblog entries can have a type attribute that identifies the MIME media type of the content: <p>Kalina, an 18-year-old killer whale at SeaWorld Orlando, gave birth to her fourth calf.</p> Although I originally regarded this as a plus for Atom, as an expert in the format for two going on three days, I'm beginning to ... read more