The most popular and widely used Internet client is electronic mail: communication through the exchange of electronic messages. Netscape Mail, Microsoft Outlook, and Eudora are a few email software packages commercially available.

There are four basic features that most email clients share:

1. Inbox: where incoming messages go and are stored until acted on
2. Outbox: where outgoing messages are stored after they are sent
3. Sent: where sent messages are duplicated and saved until acted on
4. Address book: where email addresses of contacts are stored

A sender composes a message by first addressing the message using a text string (like [email protected]). The text string is in two parts. The first part identifies a specific mailbox at a site. The second part identifies the particular site. The sender can choose a recipient from an email address book that he or she creates and which is provided by the email program. Then the sender writes text or attaches files and enters the command to send. The email program will send the email using protocols such as SMTP (Simple Mail Transfer Protocol) and POP (Post Office Protocol).

Just like the Yellow Pages helps us find names and addresses, there are online directories of email addresses for people and businesses on the Web. You will see examples of popular Internet directory sites in the FlipBook below.

Internet Directory Sites
In the next lesson, you will learn about various services available for communicating within groups online.