[New-imc] How threading works in mailman

[Sheri Herndon]

so if you want to keep threads clear and distinct, please read the following from our friends at listwork:

The reason why threads sometimes don't show up properly as threaded in
the archive is because people don't reply to the messages properly.
Each message has a unique message ID attached to it (it is in the
headers), when you reply to a message it includes the message ID of
the email that you are replying to like this:

	In-Reply-To: <W7089526090154921064870911 at webmail2>

(this is actually what is being added to this message in reply to
sheri's message), this is how mailman constructs the threading. If
people don't reply to messages, but instead compose new messages with
the same subjects, then the software has no idea that this new message
is part of the original thread, and so it puts it in its own thread.
It is only through the message-ID can it know that a message belongs
to a specific thread. 

So please, please, please, pass the word on... hit the reply button
when replying to lists, don't compose a new message!

micah