1 Mailsync is a way of synchronizing a collection of mailboxes. The algorithm is
2 a 3-way diff. Two mailboxes are simultaneously compared to a record of the
3 state of both mailboxes at last sync. New messages and message deletions are
4 propagated between the two mailboxes. If you're familiar with CVS, it's the
5 same principle, except there's no opportunity for conflicts.