There are a lot of terms that are used when talking about email, things like server and client, protocols and headers. The list goes on and on. Let's dive right in and look at what some of these terms mean. Most of these topics will be covered in more detail in this course, but let's get a general idea for now.
When talking about computer programs that share information back and forth, we often use the terms client and server. You can think about them in the same way you would think about these words in real life (for example, in a restaurant).
Simply put, a server is a computer program (or an actual computer) that has information that it gives out upon request.
When we are talking about email, the server program lives on a computer (or group of computers in many cases) either at your ISP or email service provider. This program receives email from other servers (in fact, it is acting like a client at this phase) and stores the email for you.
The client is the program (or computer) that asks for information and receives it. When you check your email, the program that you use is the client, requesting the actual emails from the server and displaying them to you.
Computer programs are not able to understand human language (our language is too vague for them to handle at this point). The programs require special codes to be able to communicate. For each relationship that a program functions as there is a special way of sending and receiving information. These are protocols. They are designed so that any program that knows the protocol can communicate with any other program that knows it.
There are 3 major protocols that you need to know about for sending and receiving email.
This protocol is used to send email from your client program to the recipient's server. It stands for Simple Mail Transport Protocol. Each domain that can accept email will have a server that responds to this protocol and will be able to tell which email server the message needs to be routed to.
Post Office Protocol is one of two protocols used to retrieve email from a server. The current version is POP3. This is typically used by clients who wish to pull their emails onto their PC so that they can read them when they are not connected to the internet.
The other protocol for reading email is Internet Message Access Protocol which is usually used when by users that have a good, constant connection to the internet. It leaves the messages on the server and allows the messages to be accessed from any computer and/or email client.
Each email has a series of entries that are sent at the beginning of the message called headers. Most email clients remove these headers (or at least most of them) when they display the messages. The headers are used by the servers and clients for many things and some that you may already be familiar with are From, Subject and To.
Everyone has heard about spam, but not everyone is clear on what it actually is. For many people, it is just email that they don't like. However, the technical definition is unsolicited email. This is email that comes from someone without being invited. Many times we give our email address to a web site and then receive newsletters from them. We may not like the emails that we get, but they are not spam in this instance.
When someone (or more specifically, some program) gathers our email address from another source and begins sending email without our permission, that is true spam.
Many email servers and clients have built in anti-spam filters. There are also 3rd party applications that attempt to find spam for you. There are many sophisticated techniques that look for certain characteristics and topics that are often associated with spam. These filters can either block the emails completely, move them to a separate folder or just mark them as spam.
Newsletters and Lists
One popular use of email is a newsletter. This is similar to a physical newsletter -- the content of the letter is copied and sent to every person on a list. To receive a newsletter, you need to sign up for the list.
Viruses, Malware, etc
It seems that people have always been around who want to use technology for bad. Email is no different (spam is part of that), but we have viruses, worms, trojans, malware and spyware. All of these terms refer to software that is written with evil intent and delivered through various communication channels between computers.
The first two of these terms are often grouped together as viruses and the distinction between them is a little blurry. The major difference between them is that a virus is passive (it gets carried around by email, transferring files, etc.) while a worm is more active. A worm will try to install itself on your computer and send itself to other computers.
The other three terms (trojan, malware, spyware) refer to programs that pretend to be something they are not (like the Trojan Horse). Both malware and spyware can be considered trojans.
Malware is software that wants to do something bad to or with your computer (similar to a virus). In fact, millions of PC's are infected with malware that sends spam emails without the owner even realizing it is happening.
Spyware, on the other hand, is designed to glean information from you and send it home. It is often used by identity thieves to get information such as passwords.
Hoaxes and Chain Letters
If you've had email for more than a couple days, you've probably already received your chain letter. These are emails that are sent to large groups of people who are encouraged to send them on to everyone they know. Some of these warn of dire consequences if you fail to do so, or great rewards if you do. Provided that you have good, up to date antivirus software, most these are harmless other than time consuming.
However, one annoying category of chain letter is the hoax email. A hoax email will sometimes warn you against some impending disaster (a deadly email virus that has been shown on CNN for example), a quotation or rant from a famous person (who never actually wrote it), an unbelievable reward (get money from Microsoft for forwarding this email) or a heart wrenching (or heart warming) story that just isn't true (send postcards to a dieing boy ...).
Oh yeah, don't forget about the online petitions -- no government would even consider looking at one of these so don't even bother. Especially if you don't live in the affected country!
Most of these hoaxes are just people having fun. Some may be made by people who are collecting email addresses for spam databases (just check and see how many email addresses are listed on the next chain letter you get). Either way, you need to verify that something is legitimate before you send it off to your friends.