I've been thinking about this, too:

I'm curious; perhaps someone out there knows…

Has anyone yet attempted to create “RSS email”, where the “feeds” served to a feedreader might be automatically synthesized from the emails themselves as things such as Person (from or to), Thread, Folder, etc?  (One could probably easily implement this as a straight layer on top of IMAP.)

[Ray Ozzie's Weblog]

Here's the problem, though. What happens when the “news item” that came to me from email drops off my newsreader's list of recent articles? With email, I can flag it for a follow-up of import the information into a task item within my PIM. Since I'm using a Mac, Newsgator is not an option. Ideas? Comments?