Ooo! This site is similar to Wallwisher, but BETTER! It is free to people ages 13 and up, so while it would be fun for students to use, mine aren't over the age of 13. However, it would be a very fun tool to use with parents to communicate questions and answers that are permanently on a board linked to my class webpage. This could save having to answer the same questions over and over while providing vital information, attachments, videos, or photos of events happening in class. This would also be a fun tool to use to collaborate with teaching peers!
Your free account allows you to create as many canvases (backgrounds) as you'd like for posting notes. While there are 25 pre-made canvases to choose among, you could also upload an image to use as your canvas. There are yellow, green, blue, or pink notes to post. On each note you can change the color and size of the font, add tags, and a due date. (A great way to remind parents of project due dates or upcoming tests.) When adding a note, there is a box at the bottom right of the canvas that shows a calendar and a way to navigate seeing the entirety of the canvas. You can also "peel off" a note, thus deleting it. Within your account, you can be notified every time a new note is posted.