How does e-mail work?

E-mail, like its older cousin, postal mail, is a ‘store and forward’ system. Messages can be sent any time, stored, and delivered when the recipient is available.

You send and receive messages using an ‘e-mail client’ such as Microsoft Outlook, or the email program built in to your smart phone. When you send a message, your e-mail client actually sends it to your e-mail server (or that of your third party provider). Your e-mail server attempts to forward the message to the recipient’s e-mail server, and if it succeeds, your part of the process is complete. If it fails, it usually tries again several times, and eventually gives up.

The recipient’s e-mail server generally stores messages, and waits for the user to request them (usually when he/she checks e-mail). The messages are then downloaded, and usually stored on the user’s system or device. Depending on the settings, a copy of each message can remain on the server for a specified time (or forever), or it may be deleted when it is delivered to the user. Leaving messages on the server provides an extra level of security, but you may eventually run out of storage space.

On-line e-mail clients

Many e-mail systems offer on-line clients. With this capability, you use a web browser to view a web page that accesses your e-mail system. You are then viewing messages directly from the e-mail server, rather than downloading them to your computer or other device. Note that, if you have previously downloaded messages and they have been erased from the server, they will no longer be available through your on-line e-mail client.

A big advantage of on-line e-mail clients is that you can check your e-mail from anywhere, using any computer or other device that supports web browsing.

 Advertising e-mails

There are two basic types of e-mail — plain text and HTML (the same HTML that is used for web pages). Today, most e-mail is actually sent as HTML, even if it appears to be plain text. This allows the sender to include almost anything that you might find on a web page such as images, links and bulleted lists. This is why you often see fancy advertising e-mail that looks just like a web page — it is actually a web page.

HTML e-mails allow web developers to include tracking capabilities, so that advertisers who send e-mail can track who views it, and whether the recipient clicks on one of the links in the e-mail.


Many people consider advertising e-mails to be spam. Of course, the definition of spam is in the eyes of the beholder.

However, there is an important distinction between advertising e-mail and true spam. Advertising e-mail is from legitimate companies that would like you to consider their products or services. It generally complies with the CAN-SPAM act, enacted by Congress in 2003, which requires a physical address on the e-mail, a functioning opt-out link and other niceties.

True spam, on the other hand, is the product of criminals, usually located in friendly (to them) off-shore locations. Like any organized criminal activity, there is a whole infrastructure within the spam industry, from top level players down to the on-line equivalent of street dealers.

Spam generally breaks down into two categories: (1) e-mail designed to infect your computer with a virus that allows it to be used as a spam-bot (a drone that relays thousands of spam e-mails, without the knowledge of the computer’s owner), and (2) people who use other people’s spam-bots (your computer, if it is infected) to send e-mail promoting illegal or fraudulent products, such as worthless or dangerous pills. Some e-mail does both. Some spam infects your computer with a virus, and then tries to sell you software to remove the virus (which it seldom does).

You can protect yourself by never clicking on a link or downloading an attachment unless you are certain that it is legitimate.