When introducing technology to a group of students in a classroom I would definitely discuss
1.) SAFETY. Don't share personal information like address, phone numbers, current plans with others. 2.) COURTESY. Too many times, posters will say things that are impolite, rude or hurtful when they believe they are protected by anonymity. This can carry over into our everyday lives. I would strongly encourage civil and respectful online communications.
3.) Your posts stay out there FOREVER. Be wise and always consider what you have said BEFORE you post. Your posts make a history of all your interactions and you don't want those to be negative.
Atomic Learning has great lesson's on digital citizenship that can be incorporated into lessons.
Teaching digital citizenship really ties in with our class rules at the start of the year along with our government units in history. We can introduce digital citizenship in the context of rights and responsibilities of citizens throughout world history as laws changed and adopted.
I feel that sharing with parents really gets the parent buy-in to support what we are doing. I believe that our websites. I also believe that students, as well as parents, should have to sign appropriate use and non-plagiarism documents.