Cacoo is a feature-rich collaborative diagram creation resource. Like similar diagram creation tools, Cacoo allows you to draw shapes, type, and drag and drop elements of your diagram. One of the unique aspects of Cacoo is that you can also upload images to include in your diagrams. The collaborative aspect of Cacoo is that you can invite other people to contribute to your diagrams. Cacoo allows you to chat with your collaborators in real-time while you work on your diagrams. Watch the video below to learn more.

Cacoo – Real-time Collaborative Diagramming & Design from Nulab Inc. on Vimeo.

Applications for Education
For students that are visual learners, creating diagrams can be very helpful in forming an understanding of concepts. I often use diagrams or mind maps in my US History classes to help students understand how multiple themes apply to a particular event. I can see myself having my US History students use Cacoo to contribute to the creation of diagram about the themes of post-Civil War Reconstruction.

Here are some related items that may be of interest to you:
Bubbl.us – Free Mind Mapping Tool
Flock Draw – Simple, Collaborative Drawing
Lovely Charts – Create High Quality Charts