In a world where every new e-mail client must support Gmail or die, this is a breath of fresh air. JMAP, from FastMail, is an API that improves upon IMAP. It is open. And free.
JMAP does everything. Instead of separate protocols with different syntax for sending email than for receiving it (and separate protocols again for contacts and calendars) JMAP combines them all under one protocol. Best of all, the push notification includes all tokens for each service, so you can synchronise changes to your entire mail account plus your contacts and your calendar in a single round trip — up to date immediately, the way it should be.
This is an excellent step. Now, how to put pressure on our favorite services/clients to support JMAP across the board?
/via Marco Arment.