MailMate release 3905 adds two significant (but experimental) features:
Integration with Calendar.app, BusyCal and Fantastical Integration with additional task managers: Evernote, Things and The Hit List These actions operate on selected messages. Actions are going to be my undoing.
An, admittedly hacky but clever, plugin for Chrome. If you are viewing a message in FastMail it will open it in MailMate. Leverage the best of both applications. Cute.
A new bundle for MailMate that sends the current message to Evernote.
On the extremely slight chance that people reading Macdrifter do not read BrettTerpstra.com first, be sure to check out his post about the experimental OmniFocus integration available in MailMate now.
Three things struck me about this feature when I first discovered it:
The developer knows his customers The plugin architecture of MailMate is pretty great MailMate 2.0 will rock my socks off