I&#x27;m pretty excited about JMAP. We&#x27;ve been planning an overhaul of Usermin, our web-based mail client, and now that we have a UI developer, we&#x27;ll be embarking on more ambitious features, like threading, off-line abilities, etc. Having threading handled automatically is already reason enough to use this, as it&#x27;s a much harder problem than it seems at first glance to solve in a consistent way across many clients and servers.<p>The fact that it also handles calendars and contacts is icing on the cake.