http://www.classdojo.com/

ClassDojo is a classroom tool that helps teachers improve behaviour in their classrooms quickly and easily.  It also captures and generates data on behaviour that teachers can share with parents and administrators.

https://www.remind101.com/​

A safe way for teachers to text message students and stay in touch with parents - free.

https://www.acadly.com/

A more efficient, engaged classroom that is free for teachers and students. Conduct realtime polls and pop quizzes, or have rich discussions. Acadly allows all this on the devices that you and the students already have.