Not WTF, but WWF. It’s a brilliant idea: create a document format that people can’t print and they won’t. Indeed, I have often heard people say, when they are printing PDF files, that they are not “printing” but “killing a tree”. You can take the ax out of their hands by using this format.
P.S. Yes, I know some tech savvy people will likely be able to get around this, but the other 99+% won’t bother and will go with this.
For more info, see: Save as WWF, Save a Tree : Home