Edmodo, which functions as a fully-loaded social network tool for the classroom, rivals popular platforms like Facebook in look and functionality while also designed with learning in mind. The site allows teachers to post lesson plans, information, assignments, and other content. Then students can post, have online conversations, collaborate, and work together or separately on quizzes, projects, and a number of other activities. Sign up is simple and free; all that is required is an email account. From there, it takes some time to set up the site to one's specifications, but teachers may find it worth the trouble.