The World Wildlife Fund hve announced a new "save a tree" initiative. They've developed printer drivers for a new document format called WWF (it's based on PDF), and they want you to use it instead of PDFs. Why? Because unlike PDFs, it can't be printed.
Okay, WWF actually is PDF, and it's slightly silly for them to call it a new format. The only difference is that the WWF format has the "do not print" flag checked.
I like the idea. I rarely print PDFs, and I would like to try to discourage others from doing so. Unfortunately, the drivers only work on OSX at the moment, so I'll have to wait.