Whiteboard and Online Collaboration, K-12

http://www.dabbleboard.com
Dabbleboard is an online collaboration tool. It has a new type of drawing interface that's actually easy and fun to use, Draw anything you want on a blank screen and it recognizes the shapes/numbers and enhances them. It’s difficult to draw a perfect square or circle with a mouse, but just make a general shape and Dabbleboard will take care of the rest. You can also re-size or flip whatever you draw. This site also allows for real time collaboration so that edits can be made to a single drawing simultaneously by several people.