Are you kidding me?
Campus Technology has a product focus on interactive whiteboards as a collaborative tool. It also has a long list of alternative technologies, but they miss the ultimate collaborative tool. Each of the technologies are involved in trying to get the written and drawn image on a white board projected or saved and transmitted electronically to students in the classroom or at a distance.
How can they miss the Tablet PC? Really folks, I can write or draw on my tablet screen and broadcast it anywhere. One can simply use Microsoft Journal to create a white space to write on or write on any of the Microsoft Office products and with other apps can write on anything. I have been doing this for years to great success. When the screen in the classroom is in front of the classroom whiteboard as it is in almost every classroom I walk into, the Tablet PC is both the projector of content and the electronic whiteboard.
I think this reaches a new height with using DyKnow Vision in a 1:1 computing environment. Each student needs a computer to receive the message and a free client download and they do not have to be Tablets.