My students have joined the Group. Now when they go to their web-logs, after logging in to their Diigo account and setting "Show Annotations > Show Group Annotations" on their Diigo toolbar, they will see the highlights of specific passages from their writing that I have left (and I can start students doing this too, it occurs to me in a very attractive flash), and my annotations will pop up on their screen when they hover their mouse over the highlights.Also good, our Diigo Groups Bookmarks page records all highlights and annotations I have made on one page. Students can use that to see all feedback I have given to specific strengths and weaknesses on all students writings.And since they're using anagrams instead of first-name usernames on their blogs, there's less of a chance of any embarrassment resulting from this "public feedback"--with "invisible ink."