Chris Littlejohn introduces Edmodo, an online platform for teachers to communicate and share content with students, organize them into groups, and assess their work. The document provides instructions for teachers to set up an Edmodo account which requires verification before being able to add students. It also demonstrates some of Edmodo's features like backchannel chat, alerts, and security controls for managing student groups. A list of 20 uses for Edmodo is included along with Chris Littlejohn's contact information.