The Notification settings area allows you turn on or off both SMS and email notifications and is accessed by clicking on your profile image in the top right off your homepage.  You are also able to edit from whom you receive SMS messages in a couple of easy steps; 

Step 1: Click the "User Settings" button

Step 2: Click the "Notifications" button

Step 3: Click the "Edit" button.  You'll see all a selector that allows you to turn off/on all SMS notifications as well as all the users from who you currently receive notifications.  You are able to manage each user separately for complete control of what comes to you.

Step 4: Choose from whom you would like to continue to receive messages by toggling the slider.

Step 5: Press "Update".