Well-intentioned email taglines inspired by sincere desire to help the planet have become ubiquitous in recent times: "Please don't print this email," "Save trees: Print only when necessary," or "Please consider the environment before printing this email."

However, the World Wildlife Fund has taken this to the extreme with a new nonprintable electronic document. Patterned after the highly successful PDF (Portable Document Format) that has revolutionized electronic document sharing and storage, the...