"I'm not sure it's very useful. Why? Well, try subscribing to one of their feeds in an aggregator for a clue. Each item doesn't map onto one story, it maps on to hundreds or thousands. Yet, in their feed they pick one that most exemplifies the class of story."
Dave, I respectfully disagree. If you got what you wanted and got all the resulting stories relating to your search term via RSS, I think you would be Really Speedily Saturated...now that would be useless (unless you're into that sort of thing). Instead, as you say, their feed provides stories that most exemplifies the class of story.
Here's one class of story...with a blurb of one, direct links to fine and a link to 30 related stories.
Another RSS story, but not the same story:
I think that is very, very useful (I wish I was talking about MSNBC Newsbot!).