This is not something I discovered on my own, and there are several other teachers that I know of who use Jing for this purpose (names are escaping me)
My use of Jing is an extension of my use of Awsome Screenshot. As long as I have been grading papers, I have been talking to myself while I grade -- a habit that drives everyone around me nuts, except for those of my colleagues who do the same. And truth be told, I'm really not talking to myself, I'm talking to the student whose paper I'm grading, except my words float uselessly unheard into the atmosphere, never to help develop anyone's writing at all.
Enter Jing. Jing is (the basic version) a free offering by Tech Smith (makers of Camtasia). Jing allows me to record, in five minute video segments, the annotation process with a vocal background track -- me giving an explanation for each annotation. To be clear, I am not telling students how specifically to correct their papers, but I can cram 20-30 mini grammar lessons (reminders of things we've already gone over) in about five minutes. As for my own learning style, after recording a class of videos on a particular assignment, I know what points need to be revisited in class due to common errors. No going back through papers tracking common errors. If I've had to verbally re-explain something four or five times for a recording, trust me, it's memorable. I also let the students know on the recording that theirs is the umpteenth "paper" where I've seen the same error, which seems to take some of the pressure off when we revisit the concept in class.
So far, my students really seem to like the correction videos, and they are effective. However, I cannot tell a lie. The are time consuming. I range from 5-15 minutes per student per assignment. It's a lot, but I feel it's worth it. What it has also done for me is to limit the number of graded writing assignments I give -- that is not to say that my students are writing less -- on the contrary, in fact -- but I've set their blogging and commenting on each others' blogs apart from the graded writing, so it serves a different purpose.
Here's a sample in an eportfolio.
What do you think?