Teachers and learners can work together and share ideas, materials and more.
Here are some tools which I might start using.
Stoodle : see this interesting post online https://blogs.umass.edu/onlinetools/community-centered-tools/stoodle/
This is a web White board which is free. Check this post online
Link to free interactive online resources http://www.teachhub.com/free-interactive-whiteboard-resources