Nick Perry has written:
> IIRC I don't think this is mentioned in any RFC but it is common practice
> among email clients to tread and sort subjects based on removing any initial
> Re: thus you should avoid inserting anything *before* the Re: because many
> clients will not associate such articles with the original...
I believe there's an 'In-reply-to: ' header that can
maintain a thread. If you choose the "reply" option, many
mailers insert the original message-id into that header.
Also, a client could be configured to look for a code string
as the first word of the subject header. If the string is
not there, the client proceeds as usual. Finding that
string, the client could assign the message to the
particular folder for the list. Then the client could
discard the string and use the rest of the header to
construct a thread.
Therefore, I still prefer that the identifying string always
be the first word of the subject. Far from confusing a mail
client, I believe that would make sorting more efficient.