Should students and teachers be Facebook friends or follow each other on social networks?
Check with your school. Some have strict rules against teachers and students being Facebook friends on a teacher's personal page (and we've heard from many teachers who frown upon the practice).
But student-teacher social networking isn't always out of line. If the teacher creates a class-wide Facebook page or dedicated Facebook group, then he or she most likely is using it as a teaching tool. Some teachers prefer Twitter to send assignments, share links relevant to schoolwork, and stay in touch with their students because the communication is pretty one-sided (a teacher tweets; the students are notified). In some schools, it's not uncommon for students and teachers to follow each other on Instagram, Pinterest, or Tumblr. Still, ask the school or the teacher what the policy is. You have the right to investigate further to make sure it's all legit.
Some educators are making use of social-learning networks such as Edmodo, Schoology, and Collaborize Classroom for their students to discuss issues and collaborate on projects or for teachers to assign and receive homework. Any teacher who requires students to join a social network should send home clear guidelines on how it should be used.