Thanks to a post by Doug Peterson I learned that Edmodo has a nice poster outlining digital citizenship guidelines for students. Yes, the poster has a clear promotion for Edmodo at the bottom, but it is still a nice poster containing reminders for students to follow. The poster is available as a PDF in two sizes, two color schemes, and six languages.
Common Sense Media also has a good poster on digital citizenship that you should check out. Their poster is a flow chart of decisions and actions for students.
Applications for Education
The Edmodo digital citizenship poster is a good one to print and post in computer labs, school libraries, and anywhere else that you want put it to remind students of their responsibilities as digital citizens.