Perhaps something like having each blob refer to an email message. Each tree would refer to a folder. Each commit would be made whenever an email is added, de

Perhaps something like having each blob refer to an email message. Each tree would refer to a folder. Each commit would be made whenever an email is added, deleted, or moved to another folder (though it would not have a reference to a parent). For indexing, you could refer to each blob with a tag that had a name that corresponds to a UID. If an email is deleted, then the corresponding tag would be deleted as well. Git's garbage collection would eventually remove references to orphaned objects and the transfer protocols would only push (or fetch) objects the other repository doesn't have. I don't know how it would scale in terms of performance though.