Comment is a way of adding information to a post. Most of the time comments are visible only to the person who has written them.
There are three different kind o f tags that can be visible in the topic section of the comment. These are the following ones:
My Own Note: My own note means that the user has written this comment. User can only alter his own comments. Comments are only visible to their user unless one of the following tags are also visible in the topic section of the comment.
Author Comment: Author comment means that the comment was made by the author of the original post. Author comments are visible to everybody.
Teacher Comment: Teacher comment means that the comment was made by a teacher. Teacher comments are visible to everybody.