Vocabulary.com - Vocabulary.com is the easiest, most intelligent way to improve your vocabulary.
Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.
Anki - Anki is a program which makes remembering things easy. Because it's a lot more efficient than traditional study methods, you can either greatly decrease your time spent studying, or greatly increase the amount you learn.
Eduflow - Digital learning that actually teaches students something
Backchannel Chat - Backchannel Chat is best in class discussion tool that is intended for teachers to streamline their class activities.
LinguaLeo - The best online service for learning English.