Just as there is far more taking place in a real Post Office and in the delivery of regular mail, there is also far more taking place in the delivery of electronic mail. However, for our purposes here, this basic analogy will suffice. This example describes the process of INTERNET email. Some popular tools which are used to create, send, and receive electronic mail over SMTP are Eudora, Netscape mail, and Pegasus.

As noted in the above analogy, SMTP stands for Simple Mail Transport Protocol. This is the standard for delivering email messages over the Internet. As the name suggests, it is a very SIMPLE protocol. Not only is it simple, but it is limiting in some aspects.

Companies such as Microsoft and Lotus have therefore created their own proprietary software products for the purpose of managing electronic mail for large companies. Microsoft developed Exchange Server, and Lotus created Notes & Domino Servers. Although these products make use of SMTP to send email to other companies on the Internet, they do not use this protocol to exchange documents and email messages between associates within the company.