"Cyrus" == Cyrus Daboo <daboo(_at_)cyrusoft(_dot_)com> writes:
| Mail systems do not appear to make any actual use of the message-id
| header other than for logging (and internally in some odd systems).
Cyrus> Message-ID, In-Reply-To and References are an integral part of
Cyrus> 'threading' email messages - its not just news. Email clients
Cyrus> that do threading will typically use those. The IMAP THREAD
Cyrus> extension also uses those.
that's primarily a client issue, or an issue of returning values from
the server (as, for example, XOVER does in news).
The more important use of message-ids in news is for clients to
request articles from the server, and for servers to offer articles to
each other - all this is done by means of message-ids. News servers
must therefore index stored articles by message-id, and message-ids
appear all the time in NNTP commands and responses. Therefore both the
no-whitespace and maximum length restrictions serve a necessary
purpose.
--
Andrew.