In composition studies, we spend a fair bit of time debating the best kind of paper comments. What's the best balance between marginal comments and end comments? How much should we address the grading criteria and how much should we provide encouragement or engage ideas? Often, however, it just doesn't matter--because students don't read the comments.
This is particularly true for electronic papers. To read paper comments on Blackboard Learn, a student must go to My Grades, click on the course, and scroll down to the assignment where he or she will see the grade and the comments I've entered in the grading block. And this is where students usually stop, although I've written "see the attached file for the grade rubric and more comments." They think, "where's the attached file?" They would have to click on the hyperlinked grade to even see the file, and most don't know this or don't bother. Since this is a complicated process, I went to the trouble to make a Screencast-o-Matic video and linked it on Blackboard--but I discovered they didn't watch it.
But today, I am feeling particularly brilliant. Our class was held in the computer classroom in order to learn to use Google Docs. For a practice activity, I asked the students to list their strengths and weaknesses as demonstrated by the first paper, which meant accessing the rubric. I walked several students through the process and directed them to the video. I was able to see everyone in the class open their graded files. Will they read the marginal comments? Probably not. But at least I know they have read the end comments and looked at the rubric.