We have had a class blog for about a term and the children love seeing their work on it. http://3b3b3b.blogspot.com Comments however have been few and far between. I know people look at it as page hits are high but comments were few. I also noticed that parents only commented on their own Childs work.
After hearing about Dr. Sugata Mitra army of grannies who encourage childrens learning I have set up Blog Supporters. I wrote to parents in my class asking for family members to give up between 15 minutes to an hour a week to encourage children on my class blogs. I asked them to leave critical educational comments to me at school and focus on praise. They leave their comment, their name, relationship to a pupil in my class and put blog supporter underneath. I now have eight blog supporters and it is a joy each evening to approve a steady stream of comments.
It is early days yet but I think this idea may be a winner.