Primary Wall is a site I just found out about from Free Technology 4 Teachers. This is a site similar to Wall Wisher but designed for education. Like Wall Wisher, Primary Wall is very easy to use and all a user has to do is click on a wall or note and start typing. However, the paid version is the only way to get the built in filtering which is ideal for education. That being said, Primary Wall has an abundance of free resources for educators such as lesson plans and ideas.
I highly recommend checking out Primary Wall by clicking here!!