Listening per user isn't fantastically efficient, but since it's only the two of us if should be fine.

(on a larger scale I'd probably have something on the end of a pipe, but I'm going to ignore that for now)

What do I need to save?

• Headers (At least from, to, date, subject, maybe type)
• Structure (From a template based on the content type. Recursive for multiparts)
• Content (The body and it's various parts)
• The original message (so I can see the 'raw' version)

Assuming all this stuff is going to also be saved by the mail system, I don't need to be able to round trip it. Folders need to be updated on change.

I should check the stats, but my feeling is that it's probably not worth it. A good chunk of mail is never opened (See: spam management), and updating folders leads to irritating locking issues (that dovecot also has but has already dealt with).

It's a cute idea, but unfortunately not worth it.