From: "Frank Haber" 

> "merged to-from, correspondent sort" option of Eudora...


I don't use it, so this description may be lame, but it merges inbox and
outbox, and groups correspondence to/from each of your correspondents. 
Within that, it's chrono.  Also makes it easier to direct both sides of the
convo to a bin of your choice, for those cursed with a high daily volume of
genuine mail.

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