E-Mail

Electronic messages sent over a network are known as e-mail. Users may send messages to a single recipient or to a group of several recipients anywhere in the world. In many cases, messages are transmitted along high-speed data communications networks in a matter of seconds or minutes. Once a message is received, a user may view it, save it, delete it, or forward it on to other recipients. E-mail programs consist of two main components: the store-and-forward messaging system and the send-and-receive interface, which is what a user sees when working with an e-mail program. The text itself usually is in ASCII format and sent via Simple Mail Transfer Protocol (SMTP). Advances in technology like Multipurpose Internet Mail Extensions (MIME) allow e-mail users to attach files—including graphics, audio files, word processing documents, spreadsheets, and even executable programs—to their messages for recipients to open on their machines.

The first e-mail message was sent by Ray Tomlinson in 1971. Tomlinson came up with the idea for e-mail when he was working for Bolt Beranek and Newman, a Cambridge, Massachusetts-based research and development outfit contracted in 1968 by the U.S. Department of Defense to construct ARPA-net, a network that would allow the government to have messaging capabilities in the event of nuclear war. To create his e-mail program, Tomlinson used a rudimentary file transfer protocol known as CYPNET along with SNDMSG, an electronic messaging system that allowed users of a single machine to leave messages for each other on that machine. He decided to use the @ (pronounced "at") symbol to identify messages that were going to be sent along the network to another machine. When Tomlinson sent his new e-mail program to other ARPAnet users, who loaded it onto their computers, e-mail essentially was born. However, it was not until years later that Tomlinson and his colleagues recognized just how widespread e-mail would become as a communications tool for educational, social, and commercial endeavors.

The Internet, which eventually replaced ARPA-net, had an immeasurable impact on e-mail technology. Although Internet-based e-mail programs emerged in the 1980s, most simply allowed local area network (LAN) users to communicate with one another. It wasn't until the 1990s, when the Internet began to function as a portal between incompatible online services like America Online and Prodigy, that e-mail truly began to evolve into the open communications system it is today. Although measuring the technology's use is difficult, it is clear that many millions of users send many billions of messages every year.

This method of quickly and easily communicating with large numbers of people is not without complications. One major issue for many e-mail users is the increasing amount of unsolicited advertisements, commonly known as spam, they receive. Many companies and individuals purchase huge mailing lists of e-mail addresses from various information sources and send unwanted advertisements to recipients. In some cases these advertisements are legal, and in other cases they are not, but the senders are quite often very difficult to trace. Many proprietary e-mail programs, such as those offered to workers by an employer, include filtering technology that helps to block spam. Users of freely available Internet-based mail services, such as Hotmail and Juno, are more likely to receive spam.

Another problem inherent in an open communication system like e-mail is the ease with which viruses can be spread via e-mail message attachments. Many virus programs are disguised as attached files from colleagues or friends. Once they are unwittingly opened by a recipient, the virus reads the recipient's address book and forwards the virus on to each user in that address book. Because the e-mail looks as though it was sent by the victim of the virus, the likelihood that future recipients will open the disguised virus is quite high.

As e-mail technology has extended its reach across the globe, individuals and businesses have begun to use it for increasingly diverse reasons. A multitude of Web sites now exist that allow individuals to create free personalized greeting cards they can e-mail to family members and friends. Students in online courses are able to e-mail their work to professors, who then offer feedback via e-mail. Online retailers quite often e-mail receipts to customers within seconds of a purchase. These same retailers also may e-mail customers to let them know when their goods are actually shipped, and if a customer has indicated they would like to receive information in the future, they may send e-mail messages regarding upcoming promotions or special deals. Some online travel companies e-mail discounted fares each week to a list of people who have subscribed to such a service. While there is no way to predict how e-mail might be used in the future, new ways in which the technology can be used for educational, social, and commercial endeavors are certain to develop.