On Wed, 13 Jan 2010 00:39:14 -0500, Scott Morrison <smorr@indev.ca> wrote: > > Maybe a better approach would be content addressing (see below). > > Content hashing -- good Idea (& not something that has hit me before) > -- better than Message-Id as I believe there are still some MUA /MTAs > that allow messages without message ids. The only potential issue > with this is that it is critical then to preserve the message source > against encoding changes though that shouldn't be too hard to avoid. Another problem with content-based naming for messages is that most of the messages in my mail store that I consider duplicates don't actually have identical content. (One is sent directly to me via CC and the other is sent by the mailing-list software *after* appending a footer to the message.) That said, notmuch already does use a sha-1 sum as the message identifier for any message that does not have a valid Message-ID header. So there's definitely a place for this. -Carl