Merlin Mann of 43 Folders has 2 ways to make RSS readers smarter (edited to give the gist):
There's two significant features I've been wishing for in my beloved newsreader, NetNewsWire [snip]
- Per-feed expirations that let me select how long I want to subscribe to the feed.
- Smarter Dinosaurs let you display any feeds that haven't seen any activity over a period of time that you choose.
Number one I'd never even considered before in my aggregator (aka "feed reader" or "newsreader"). Merlin is particularly interested in expiring feeds that are guaranteed to be uninteresting after a time period (comment thread, delivery notifaction). This might be superceded completely by having those "smarter dinosaurs," which help you expire inactive blogs. It would need to be smart enough to count the frequency of 404 errors, not just assume anything with a 404 is bad. Maybe I'm connecting on a flaky cafe wireless connection.
I have seen the "dinosaur" function in BlogBridge and GreatNews (I think). Basicaly, they let you know when there has been no activity. BlogBridge also has the beginnings of a Dinosaur tool to help you find outdated feeds. I would love that to be sensitive to which folder I've stored the particular fed, so that I could do two week dinosaurs in a comment feed, for example.
The one caveat is that I like to keep my "deleted" feeds handy, so that I don't go through the cycle of deleting then resubscribing then discovering why I deleted... The thing I like about SharpReader and some others is that I can "delete" feeds by setting their update frequency to "never." I still have them around, but they don't get in my way.