Blogging ideas for my third graders

I have been thinking a lot about blogging this week. First, the concept is new to me even though it seems very similar to what we do in the conference areas in our "classroom" for UMUC. But then I started to think about my third grade students and how they could use blogging to help them in some way. I immediately thought about their novels that they read in their small reading groups. Each novel is based on the students' level or reading ability, so in my class I have 4 groups for 24 students. The groups are not equal in number, but range from above third grade to way below third grade with two groups in the middle. Currently my groups are reading Charlotte's Web, Frindle, Sarah Plain and Tall, and Biscuit. I thought about being able to set up a blog for each reading group and they would be given a question each week that they would need to respond to and maybe even need to answer one from another person in the group. The students in the group and I would be the only ones able to participate in the group. This way I won't have to worry about outside influences are the students. Using the blog I would be able to have an understanding if the students comprehend what is occurring in the novel and if they are able to contribute to the overall understanding of the group. One of the nice side effects would be the practice with typing on the computer and just practice with the computer. As the students get used to the activities I could require them to add a picture or something else. I am not sure how I would manage the time factor for this project since I have 2 computers and 24 kids, but maybe through a week all the students would be able to get on or maybe even using adult volunteers, which I have a plethora. These are just my thoughts about blogging in the classroom if you have any suggestions to improve please let me know. I am always open to new ideas.
:)
Kim