Connecting (a Network) to the Internet
Email is one of the main parts of the Internet. What has caused some confusion in recent years is that instead of being completely separate from the World Wide Web, email has been integrated into it in a web-based format. However, when you are sending email from a web browser, only the interface is different; you are still using the email function of the internet. The web page and browser are acting as your email client.
The way email works is not so different from the way the post office works; the main difference is that, obviously, email is electronic. But, the process is the same. You address a message, you write it, you send it, it gets delivered. It really isn't much more complicated that that.
Instead of using the same protocol as a web page (http)
or ftp, email has its own protocol, called Simple Mail Transfer Protocol
(SMTP). When you send a message, your email client (or program,
like Outlook, Apple Mail, Yahoo on the web, etc) uses SMTP to send out
the message to the local mail server. That
mail server then sends the message on to the appropriate mail server
that your addressee uses. This is done in much the same way as
a web page address is resolved 
.
The only real confusing part is that a different protocol is used for incoming mail. This protocol is called POP or IMAP. POP stands for Post Office Protocol. This Protocol drops the sent message into your "in box" on the server until your email client connects and downloads it.
Why do we need both SMTP and POP? 
.
IMAP is slightly different from POP and is becoming the
protocol of choice for many. The Internet Message Access Protocol (IMAP)
was developed at Stanford University in 1986. The major difference you
need to know about is that IMAP can keep your mail on the mail server,
whereas with POP it is downloaded to a computer. This can be a
valuable service when you are traveling or don't use the same computer
all the time.
Read about the advantages and disadvantages of POP and
IMAP .