E-mail was an electronic message exchange protocol (electronic-mail) used on 20th and 21st century Earth. With the advent of computing technology and the development of huge international, corporate, private, public, and military networks in the late 20th century, e-mail became a fast, free and effective means of conveying information around the planet.
In 2000, Shannon O'Donnel suggested using e-mail to spread the word of Henry Janeway's campaign to save downtown Indiana from the development of the Millennium Gate. According to her, "e-mail(ing) every computer within a hundred miles" would only take a few hours. (VOY: "11:59")