Although invented in the 1960s, the popularity of e-mail took off in the 1990s. As the cost of connecting computers to the Internet (see entry under 1990s—The Way We Lived in volume 5) fell, e-mail became the easiest way for computer users to send written messages to one another. Its advantages over the regular mail are speed, convenience, and low cost. Word-processed documents, images, sounds, and moving pictures can be e-mailed around the world in a matter of seconds. While "snail mail" (via the postal system or an overnight service) is still important for transporting packages, legal documents, and the like, e-mail is set to become the key personal and business communication tool of the twenty-first century.

Since the 1990s, e-mail has revolutionized global communications. Curiously, it was developed during the Cold War (1945–91; see entry under 1940s—The Way We Lived in volume 3), a period when global communications...