A Walled Garden
Edmodo, with it's "facebook-like" interface, creates a walled garden for your students to share and learn. Teachers create a space and then give students a code to login. No code - no access. This means your class space is private for your kids. Students can share ideas (to the class or techere - not individual students) and upload assignments for the teacher. The teacher also can organize folders of handouts, resources, links, videos etc. Check out the links and videos below to learn more.
Quick Guides to Edmodo
45 minute tutorial for teachers
iOS app for Edmodo
Reflections from a teacher who uses Edmodo