Email is abbreviation for "Electronic Mail". It is one of the most common uses of the Internet today, secondary only to the World Wide Web. Although originally spelled with a dash (E-mail) popular use has seen the dash eliminated. This is evidence to email's penetration into everyday life and its importance. While email is often perceived as an inclusive system, there are actually a series of protocols governing its application which are constantly being refined. Notable among these are SMTP, POP3, and IMAP. No fewer than four different computer programs and often as many as eight may handle a typical email message in the few seconds between its transmission and receipt.
The first email systems were developed at SCD and MIT in 1965. Incompatible with each other, each system was designed to facilitate message delivery between users on a single machine. As there were no large computer networks at the time, the need for interoperable protocols had yet to be realized. When ARPANET engineer Ray Tomlinson decided in 1971 that he wanted to send a message to another user on a remote computer, he chose the @ symbol to separate the user's name from the machine's name. He modified the leading email program of the time, SNDMSG (which Ray himself wrote), to accept and process these new addresses. Within just a few years, Ray's protocols had been implemented on virtually every networked computer in the world.
Although email is often credited with making the world smaller by fostering communication, it has also brought with it a fair share of problems. Email communications are usually plain text transmissions over unsecured channels, passing through many gateways on their way to delivery. Thus, the interception of email is not difficult to perform. Also, backups of email delivery machines can save copies of messages for years, even though they had been deleted by the recipient. However, the most visible problem associated with email today is spam, or unsolicited bulk messages. Estimates of global spam rates hover between 70 and 80 percent of all email successfully delivered, and some popular systems can see their spam rates rise well over 99 percent.