e-mail

The basic structure of an e-mail system. A message is sent via a telephone line and stored in a central computer. The message remains there until the recipient calls up the central computer and collects the message.

Messages sent electronically from computer to computer via network connections such as Ethernet or the Internet, or via telephone lines to a host system. Messages once sent are stored on the network or by the host system until the recipient picks them up. As well as text, messages may contain attached text files, artwork, or multimedia clips.

E-mail communications predates the Internet itself, but usage of e-mail has boomed because of the growth in computer and internet access. E-mail has become a crucial part of much business communications and marketing activity. Subscribers to an e-mail system key in messages in ordinary letter form on a personal computer, and ‘drop’ the letters into a central computer's (e-mail server's) memory bank. The recipient ‘collects’ the letter by calling up the central computer and feeding a unique password into the system. Due to the high speed of delivery, e-mail is cheaper than an equivalent telephone call or fax.

The usefulness of e-mail is being compromised by the high volume of spam (junk mail) being sent over the Internet, much of which is offensive to its recipients. In addition, e-mail is also being used to spread viruses through message attachments. In a 2007 study the Radicati Group found that worldwide e-mail volume exceeds 140 billion messages a year and is growing by 25% each month.