The teacher started using Google Docs this semester as a way for individual students to write reflections shared only with him that he could then easily comment back on using the Google Docs comment feature. His request made sense as a way for the teacher to make notes on the same document but for himself only, which he could then refer back to when writing end of term comments at report card time.
As I've used Google Docs a lot myself to collect work and then comment back to students, my initial answer was no since Google does not support separate rights on the comments (yet?). However, it later occurred to me that combining Diigo with Google Docs might do this.
If you aren't familiar with Diigo, it is an online social bookmarking service. However, what makes it stand out from other similar services is that if you install a browser add-in, you can annotate most web pages with highlighting and sticky notes. These annotations can be shared with everyone, a limited group to which you are a member, or only with yourself. These annotations are stored on Diigo's servers and appear back to you anytime you access the original web page from any computer (if you have the browser plug-in enabled).
Unfortunately, It turns out that you can not highlight text using Diigo in a private Google Doc. However, the sticky note feature does work. Therefore, you can use Diigo sticky notes to facilitate private comments to yourself on a Google Doc you are sharing with others.
