Dec. 30, 2014
10:39 p.m.
Thank you for the CC, it is appreciated.
We have no problem with changing, or even completely dropping X-Message-ID-Hash. Mail-archive.com doesn't look at it. Instead, we parse Message-Id and do calculations from there.
By the way, direct use of message-id seems to be growing in popularity. For example, I constantly see links to Debian's msgid-search. I think that trend is going to continue, boosted by the fact that it is easy to embed a link to a long URL in HTML mail.
Jeff