Academia.edu - Academia is a website where you can share papers that are written with other users. You can use a Google or Facebook account to sign in to the website.
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.
Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.
Clever - syncing between education applications for K-12 schools
Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.
Claroline - Claroline is a collaborative eLearning and eWorking platform.