Learning management system with a very visual user interface for the teacher. Teachers can create sequenced lessons.
Limitations: Free for up to 30 students per teacher.
Online Meeting Channels, Audio Conferencing, Screen Sharing, File Sharing, Webinar and Telepresence Solutions
Limitations: 500 free meeting minutes. Up to 4 people in room.
Social network for language learning based on the premise of living in a town with other learners of that language. Includes various means of communicating, including forums and voice chat. Also includes language learning resources.
Site offering a variety of apps that teachers can use to create activities and that students can use on their own. Intended for EFL, but would also be useful for other languages in some cases.
Limitations: As of 6/9/2016, no new registrations are allowed, although the site can be used without registering.