In order to protect student privacy and prevent mischievous behaviors- such as cyber-bullying, Imagine Math does NOT provide a social platform for students to communicate with either each other or their regular classroom teacher.
They can only access Imagine Math's Certified Math Teachers when working in the Guided Learning activity of any given lesson in Imagine Math. (See How do students connect to a Live Teacher?)
The only option you, the teacher, has available for communicating to a single student through Imagine Math is the messaging tool found in the Activity Feed of the lower right corner of your Imagine Math Home page. (see Messaging a Single Student)