Twitter in the Younger Grades?

This week I was reading about microblogging and Twitter in particular. While I had a Twitter account from a year ago or so, I never accessed it. I only signed up to see what my teenage sons were talking about. Now that I've had to revisit Twitter for my Ed Tech course, I'm seeing it in a new way. I guess I never realized that there was more to Twitter than following Oprah! Our assignment for the week was to come up with a Twitter lesson plan that is relevant to what we teach. Being a first and third grade teacher, I was stumped on how I could possibly use it with my students. I decided to aim for a lesson with my third graders as I thought I would have more success. As I was searching on google for inspiration, I was quite surprised by the amount of blogs out there with ideas for using Twitter in the class. Although, most of them were geared to higher levels than I teach. For the younger grades, Twitter seemed to be used more as a communication tool with parents. I use a blog for that so I didn't feel that would be useful for me. I didn't want my third graders using Twitter for personal information so I decided to have them created fictional Twitter accounts for biographical figures that they were reading and "Tweet" from their character's point of view. I hope it's a lesson that I will be able to try, as I'm going to have to speak to administration as well as the parents on their feelings about using Twitter with 8 and 9 year olds. I would be curious if anyone had any experience they could share about using Twitter with younger students.