David Bremner on 2009-12-15 08:05:13 -0400: > Recent discussions on IRC (I forget with whom, sorry), brought me back > to thinking about syncing notmuch with imap. In addition to the flags > \Seen, \Answered, \Draft, \Deleted, and \Flagged, imap servers can > optionally support user defined keywords (i.e. tags). At least courier > and dovecot do. These keywords are imap "atoms", which, without tracing > though the BNF  completely look like they can can have (ascii) > alphanumeric, and punctuation other than brackets, quotes and "%", "*".
I am also very interested in syncing tags between computers. I started implementing storage of tags in message headers. It's has been done before - several mutt extensions and systems use X-Label. This approach offers several advantages to notmuch dump/restore and IMAP flags: - compatability: most mail clients can search on headers, so even if you're not using notmuch full-time (squirrelmail? phone?), you can get some benefit from it - works with offlineimap without further effort: no new transport mechanism required - a migration path: text-based mail sorting tools like procmail can easily set headers - backups are easy: you can't miss backing up your tags because they're in the messages There are security concerns (need to strip incoming messages of tags so no one tags your mail for you), privacy concerns (if you forward the entire message as an attachment, may want to strip tags), and space concerns (how many flags?), but I think they can be worked around. I haven't gotten very far with my implementation due to time constraints. It reads tags fine, but I haven't implemented writing, which is the involved part. I hope to get to this between Christmas and New Years, but who knows.