One of the biggest roadblocks I have had thrown at me when I try to show people about being paperless and using online tools to mark and give feedback, is that they prefer writing their comments on paper or that they don't like the idea of marking online. That is their personal preference, but I find that the richness of the comments online can create greater feedback, and should increase student achievement and understanding.
Let me explain. Even before I used Google Apps, I would use the review: comment tool in MS Word when students handed in work. Other colleagues have used TurnItIn for commenting for both drafts and final work. Using the comment tool worked for me as my slightly messy writing was made clear by typing, and I had much more space to write. But it was still a one-sided feedback; I did not find out from students whether they had even read it. And most teachers will tell you that we are not even sure if the feedback sinks in, especially when we see the same mistakes being made.
So why use the same comment tool in Google Apps? Because the students can respond/resolve the comment.
Example (the student's Action Plan on helping reduce Poverty):
I am not clear on this inclusion of this charity. It seems to be more for renters than people who are hungry.
Whoops your right i'll change it right away
Student Alright i changed it
What I explained to my class is that we are now going to be creating a feedback loop: I comment, they reply and 'resolve'. This would tell me that they have read the comment and acted upon it. I am happy to say that I even saw some students' heads nod in understanding!
So far this seems to be working, though I have had to remind the students to go into the document and respond/resolve the comments. I am getting my feedback that they have read the comment, and can see the changes taking place in the document.