Google Classroom is an under-rated messaging platform for teachers and students. When used effectively, the messaging/commenting capabilities in classroom lead to rich conversations and learning moments between teachers and students. The 2018 update to Google Classroom significantly changed the location and emphasis of three commenting options in Google Classroom.

Class Comments

Class comments are visible to the entire class. Google Classroom doesn’t support student:student messaging, so the class comment feature is the only way that students can communicate directly to one another.
Everyone in the class can see class comments. Teachers have the ability to disable this feature entirely, delete an individual comment, and mute an individual student.

Private Comments

Private comments allow a student to ask a question directly to their teacher. The 2018 update to Google Classroom places a lot more emphasis on private comments.  Private comments are a wonderful way for students to ask for help, get clarification on an assignment, and receive personal feedback from their teacher.

Question Responses

If you use the question tool in Google Classroom to ask a free response question, students have a third way to respond through Google Classroom.  The response in this area should be directly related to the discussion question. Submitting an answer will mark this assignment as “done.”

Source: Managing Comments in Google Classroom (2018 Update!) by John Sowash, published by Tech & Learning