http://www.dabbleboard.com/tour
Dabbleboard will help students visualize, explore and communicate ideas. It makes drawing diagrams, jotting notes and sketches, and sharing work online easy. Dabbleboard comes with a library of objects for piecing together organizational charts, mind maps, network diagrams, floor plans, photo annotations, interface designs, electrical diagrams, etc. Users can share Dabbleboard work via e-mail and then watch, in real-time, as changes are made to it. There's also a public library of Dabbleboard drawings that can be copied and edited.