Pinside is a free online sticky note service. Pinside can be used to create boards of notes for yourself or boards to share with others. You can create a mix of private and shared notes within one account. Sticky notes on shared Pinside boards are designed for creating to-do lists. As each item on the the notes is completed you and or your collaborators can delete completed items.
Applications for Education
Pinside could be a good little tool for students working on group projects to assign tasks to each other and check them off as they go. Pinside could also be used by students to create a board of action items for each of the courses that they are taking.