Sean Lyndersay has updated the specification for “simple list extensions”:http://msdn.microsoft.com/windowsvista/building/rss/simplefeedextensions and posted a helpful “description and examples”:http://blogs.msdn.com/rssteam/articles/SimpleListExtensionsExplained.aspx.

The Simple List Extensions (SLX) is a set of extensions designed to do two things:
(1) Make it possible for publishers to declare in their feeds that the feed really represents a “list” (more on that later).
(2) Allow publishers to mark up their lists (and feeds) to note which sub-elements of the item (or entry) represent properties that the user may be interested in sorting or grouping on.

I’ve blogged on Simple List Extensions in the past and think they represent a way to make RSS more effective for things like job feeds.

The major missing ingredient is still a publically available client that implements the specifications. Not even the IE7 or Longhorn betas support it.