Once you register for a MindMixer account, your account settings will automatically default to send one weekly email for each MindMixer site with which you've visited. You can easily change the frequency of these emails, or unsubscribe.
To edit your email notifications, click the drop down arrow next to your name or the gear icon, and choose "Account Settings."
From there, the third tab labeled, "Preferences" will direct you to choose your email preferences. Be sure to click "Save Changes" button at the bottom of the page when you've completed your account updates.
Note: Under the title of each notification it will give a more extensive explanation of what those updates entail.