Short for “electronic mail,” e-mail was invented in 1971 by computer engineer Ray Tomlinson (1941-) who developed a communications program for computer users at the Advanced Research Projects Agency (ARPA). The result was ARPAnet, a program that allowed text messages to be sent to any other computer on the local network. ARPAnet is now hailed as the Model T of the Information Superhighway. The technology expanded in the 1970s with the use of modems, which connect computers via telephone lines. Within a decade of its introduction, e-mail had become widely used as a communications mode in the workplace. In the 1990s usage expanded rapidly to Internet users at home, schools, and elsewhere. Some technology analysts call e-mail the “killer app” of the Internet, the most powerful tool on the worldwide computer network.