As we look forward to New Gradbook, I have a teacher asking for a feature.  She's asking for:

 

"...a little symbol, like a notch in the corner, to show that the teacher has made a comment on the grade in the gradebook.  In [our grading system], if we made a comment, we could see in the box that a comment was there, without needing to click on it."

 

So something similar to when in a spreadsheet in google, and when someone makes a "comment" to the cell, you see a little corner tab.....

In this way the teacher knows visually, quickly, which students received a comment -- without having to enter each graded item in the Speeedgrader.