A Social Aggregator?

Dave Winer pointed to this article, RSS: What is a ‘River of News’ style aggregator?, and it got me to thinking. I’ve been looking at social bookmarking a lot lately, especially Scuttle, for a little project I call the great big law school directory. What about social aggregating of feeds? Let folks add feeds as bookmarks, add tags to the bookmarks, run a serverside aggregator, shake, stir, repeat. Browsing by tags of course, RSS feeds of feeds of course, ‘River of News’ style, of course.

But here’s the bing! Parse the feeds as aggragated looking for category tags in the feed and add those to the folsonomy that is built around the feed. That would be cool.