This article at the Harvard School of Education blog breaks my heart. A teacher was trying to facilitate discussion but the observer realized that after 5 months, the kids didn't even know each other's names. This is sad and heartbreaking. Students matter and a name is music to their own ears. Not knowing each other is heartbreaking and I know it is hard, but we have to work to help kids know each other in the classroom.
It isn't enough to talk about digital citizenship. Experiential teaching is the most powerful teacher. As your students are learning about it, they should be experiencing it (not just the privileged few who have it at home) but at school. The Digiteen project is one high-intensity way to do it. Here's a teacher's reflections upon what the project is about.