I had personally seen many guys taking print of such things which are not important.Or many time in the organizations employees are asked no to take print out of the documents handled to them due to security reasons, but they do.
Paper are made from trees and its not right to waste papers, so in order to save trees, an organization WWF, its an organization which works for the safeguard of Trees and Animals Or simply nature in the world, has taken a step.
WWF has made a new file format, WWF, which is same as PDF but print command is not there.If you got any WWF file you will be able to read it inside any PDF reader but wont be able to take its print.
To use it simply download and install it from below link, currently it is only available for Mac OS X10.4 or higher, windows version will be soon out, and then just use Save As .WWF while saving any document,that’s it.
Actually WWF is a PDF file in which print is command disable.