Woah! Thank you so much - this was great and I definitely would never have found it on my own!It is sort of hidden -
Log in to yiur Disney Movie Insiders account
Click on your name, then scroll down to Settings
Under settings below all of your personal info is a link to manage your email subscriptions, Click that link.
Yiu will get to a screen which allows you to opt in or out to the various Disney Company emails on all diffeeent topics; check the box for Disney Movie Insiders and then Save. Thar should get you on their email list for DMI updates.