So I've been using Twitter with my classroom now for a week, and things are going well. I have 75% participation from my parents. I have at least 1 administrator following also. I plan on getting some feedback from parents and staff to see what they think of the idea, but it seems to be working. For me it allows me to give specific information about lessons and such for parents to see. I've not tried using it with direct messages (a little concerned about privacy), but it might be a use for it too. I'm going to continue to use this, so again I'll keep you updated.