[Jon Udell on Extending RSS, in response to a post by Sam Ruby]: I see no problem with Rory and his legal pals agreeing on some tags (like <asbestos>) which they'll use by mutual consent. The immediate bottleneck is getting software into their hands that enables one user to pop such a tag into a feed, and another user to discriminate based on the tag. And then getting them to the point where they can actually experience that.
. . . .
Until and unless the likes of Rory and friends can start bootstrapping the process of creating and consuming customized feeds, there's no scaling issue to worry about.

Jon's point is well-taken -- using Radio or other content syndication tools in the daily workflow is hard enough, much less doing the extra work it takes to customize the XML feeds with topic-specific categories.  And then there is the additional layer of finding aggregator tools that can use custom tags.  Nevertheless, I am optimistic -- this post, for example, is being routed to Rick Klau's new multi-author weblog called Radio for Lawyers.  (One more tool for bootstrapping.  Thanks Rick for getting the ball rolling!)  

What's more, many lawyers are already using the category function of the RSS spec, which is built-in to Radio, to create specific topical legal feeds. (e.g. Rick has law, accounting, CRM etc.; Ernie has copyright, KM, etc.; and I provide public information about WV Supreme Court cases in recent, civil, criminal, and family categories, as well as feeds about legal information standards, access to court records, and court webcasting.