NetNewsWire 1.0.7 adds support for the feed protocol. Wes has suggested that MIME types and helper apps are the correct way to handle this, but modern browsers seem to have practically given up on good integration between MIME types and other apps.
I took a few minutes to read the feed protocol specification. It needs a little refinement, particularly the part about extensions (sending commands and parameters with the URL). For feed URLs with no commands, I don’t like that
feed://http://example.org/rss.xml is the same as
feed:example.org/rss.xml, but if you introduce a command, the real protocol (“http” or “ftp”) seems to be required. The “how to process a feed URL” section continues this confusing by saying that the real part of a URL is denoted by either “:” or “.”, but all the examples always include “http://“, which implies that
feed://command/example.org/rss.xml would not be valid. Even more confusing would be an example like
A minor gripe, perhaps. Anyway, we’ll see whether it catches on.
Another smart experiment with making subscription easier (or at least not as disconcerting for new users) is the work done by Jason Shellen to apply CSS to the Atom XML file. The addition of a proposed “info” element helps describe what the user is seeing.
Update: Brent points to Dare Obasanjo’s pre-draft feed URI spec. On first glance it appears to be a more formal but less complete spec (not necessarily a bad thing). Apparently this is a somewhat unorganized effort.