It seems that Dave Hyatt, one of the Safari developers, has also recently started using NetNewsWire to read his news. His two most recent posts talk about his thoughts:
More Thoughts on RSS Then the RSS aggregator becomes useful as a filtering mechanism, with the Web browser being used only to view the articles that you ultimately decide to read. In this mode it seems like HTML display is hardly even a requirement for the aggregator application, since you basically just want to speed-read the excerpts from the RSS file and only go into the full blog if you decide that it's worth following up on.
His other comment about having RSS feeds automatically handled by apps using some sort of protocol signifier is a really good idea, and takes care of Graham’s comments on “how to get started with RSS”:
Rise of the Uber-browser I'd like to be able to click on an RSS file link in a browser and have it automatically pass that off to my news application. One click should be all it takes to get me subscribed, whether that click happens in a mail app, a Web page, or inside NetNewsWire itself. A protocol handler would work for this. I think of this as being somewhat similar to the "view-source:" protocol supported in many browsers, i.e., you could just say "rss:original-url" or "feed:original-url" and have the appropriate application configured to handle feed subscriptions.