Forum

I think that the taquilla forum is the most appropriate to post this idea:

Tags are a great way to group emails from various folders but it is
cumbersome to use tags when you want to make too many groups of emails.

1st example,
say that you buy a lot of things from ebay. For each item you buy, there are
many different emails you might get ( emails from the seller, emails
from paypal,
emails from ebay itself etc) and you might want to keep all these emails in
different folders (a paypal folder for keeping all paypal emails, an
ebay folder
for keeping ebay emails etc) even though these emails are related since
they
refer to the same situation (the purchase of the item).

2nd example
say that you usually attend seminars. For each seminar there may be a lot
of emails involved. emails related to payments, emails related to info about
accommodation, emails send/received from/to friends about the seminar etc.
All these emails are usually kept in different folders but they are all related to each other
since they
all refer to the same seminar. One could assign them a tag
(say: MathSeminarChicagoFall2011)  but that is not handy. Tags are usually
simple and general (e.g. Payments, Personal, Jokess, Important).

The solution would be to relate messages through an entry in their
headers. Such entry could be named as "Relations:". Each one of these
emails will have
the message-ids of its relatives into its relations entry.
In short the "Relations:" header entry would be similar to the common
"References:" header entry
but it would be easily editable with something like drag and drop in a
Relations" window.
By pressing a button (or via the message's right click context menu) one
could open
the message's Relations window and then drag-drop other messages in it
making them
related to the active message.

This way, if someone would like to see all the emails related to a specific seminar he
could simply open one of the emails involved and check its header. 

Regards
Giorgos

Thank you rkent for the detailed reply.

Giorgos