One of my favorite sites is Edmodo. Edmodo is a free "secure social learning network for teachers and students." I first began using Edmodo as a professional learning network. This year, I began using it with my students. My students and parents love it!
On first glance, Edmodo looks like Facebook. There is one twist. It is very, very secure. You can create a class group where only you, your students, their parents (with a special invite code), and invited guests can correspond with each other. My students love the Facebook feel. My parents and I love the security.
Edmodo is so much more than a social network platform. As a teacher, you can use it to create assignments, share links, communicate with your students about homework, etc., and offer encouraging words. As a professional, you can communicate with other teachers throughout the country. You can post a question and within minutes receive a response.
Edmodo is a staple in our classroom. My group of 4th graders is learning digital citizenship in a hands-on matter. Have I ever had a student use the site inappropriately? No! They have known from the first day that their parents can view whatever they do and anything they post goes straight to my phone. Edmodo is a powerful tool!