Neat and handy tool for visualising ideas.
"The whiteboard was invented by Martin Heit, a photographer and Korean war veteran. The idea was originally developed for having next to a wall phone to write messages on. During his work with film he realized that notes could be recorded on film negatives using a marker pen and could be easily wiped off with a damp tissue. Early whiteboards were made out of film laminate, the same glossy finish found on film negatives."
http://en.wikipedia.org/wiki/Whiteboard