What are some alternatives?
Google Classroom - Google Classroom is your mission control for class.
newrow - Create your online school and deliver interactive content.
Moodle - Moodle - Open-source learning platform | Moodle.org
PowerSchool - PowerSchool provides a K-12 education technology platform for operations, classroom, student growth, and family engagement.
Edmodo - Where Learning Happens
Teachable - Create and sell beautiful online courses with the platform used by the best online entrepreneurs to sell $100m+ to over 4 million students worldwide.