Either way, WWF is your answer. No, not the World Wrestling Federation -- WWF stands for World Wildlife Fund, but it's also the extension given to the new WWF document format. It's virtually identical to (and interchangeable with) PDF, but with one difference: it can't be printed.
Here's how it works: You install the WWF software (now available for Windows and Mac) on your PC, then "print" documents in that format (just like you do when creating PDFs). Any WWFs you receive will automatically open in your default PDF viewer. And those you send can be changed to PDF to make life easier for the recipient (whose system may not know how to open WWFs).
Neat, huh? It may seem a little heavy-handed to force a "green" agenda this way, but think about how many people crank out unnecessary hard copies just out of habit. Here's a little more incentive:
[via Digital Inspiration]