By now the news has rattled around pretty widely that Microsoft is adding RDF Site Summary (RSS) support to Longhorn. Inasmuch as I've been publishing RSS on various Web sites since mid-1999, perhaps I'm qualified to reflect on some of the implications of this move. I think I speak for a lot of early adopters when I express mixed feelings about Microsoft's entry to the RSS ecosystem. It's sort of like having a favorite coffeehouse that...
you share with a small group of friends suddenly get featured on the six o'clock news. On the one hand, it's nice to have your own good taste validated. On the other, things inevitably change when your little private world suddenly gets popular.
As with any other shift in the feature set of Windows, this move will have an impact on the ISVs of the world. Right now there are hundreds of ISVs, freeware authors and open source projects providing a rich variety of RSS tools of all sorts. Inevitably, the entry of Microsoft into the RSS market will simply drive some of these players straight out of business. On the other hand, a few nimble ISVs will take advantage of the new Longhorn capabilities (such as background synchronization and the unified RSS feed list and item store) to build some new and innovative applications.
Microsoft is also taking advantage of the built-in extensibility mechanisms of the RSS standard to develop their own flavor of RSS, adding ordered lists atop what's already in the spec. Here, although some people seem to fear a return to "embrace and extend" (more popularly known as "smother and crush",) it looks to me like Microsoft is doing everything right. RSS 2.0 was designed to be extensible, Microsoft followed the rules, and they're licensing their extension back to the community under a Creative Commons license. It's likely that the new elements will break some poorly designed software, but it's not Microsoft's fault that some people can't read a spec and grasp its implications.
The most important thing to keep in mind for the moment, though, is that this is a Longhorn announcement. So far, this doesn't have any impact on tools running on any Microsoft operating system that's actually shipping -- or, indeed, on any tool likely to have a significant market share in the next year or more. That poses an interesting quandary, both for ISVs and for Microsoft itself. If you're writing a new RSS tool (or adding RSS support to an existing application such as Outlook), do you target the new APIs, and limit your sales to Longhorn early adopters? Do you ignore the new code entirely so you can deploy anywhere? Do you use the new APIs on Longhorn, but fall back to your own code on older versions of Windows, at the cost of maintaining twice as much code in the product?
Microsoft will feel this quandary more keenly than anyone else. Now that they've made a big public commitment to RSS, the pressure is going to be on them to come up with some stunning RSS-enabled applications. If they limit these applications to running on Longhorn only, they'll upset a lot of existing customers. But if they decide to port the RSS APIs to older operating systems (as they're already doing with the Avalon and Indigo API sets), they'll remove one more reason for anyone to upgrade to Longhorn.
On the whole, I'm glad to see Microsoft supporting RSS in a big way. As both a producer and consumer of RSS feeds, I'm happy to see it becoming easier and easier to get the information that I want, and to push my own thoughts out to my subscribers. For those of us in the business of managing information, it's all about having good plumbing, and there's no better place to put the plumbing than right in the operating system.
Mike Gunderloy is an independent developer and author working in eastern Washington state. His recent books include Painless Project Management with FogBugz (Apress) and Coder to Developer (Sybex). You can read more of Mike's work at his Larkware Web site, or contact him at MikeG1@larkfarm.com.