From the article:
In this second installment in the Ars Guide to Online Security, we'll cover the basics for those who may not be familiar with the different types of malware that can affect computers. Malware comes in a variety of types, including viruses, worms, and Trojans.
It seems like every year or so, articles like this surface. When I used to help home users, I avoided such discussions, which most of the time were confusing in their technical descriptions.
To them, all malware was a virus, and that was fine as far as I was concerned. I preferred to focus on secure policies and procedures, such as:
--> handling email attachments.
--> not installing anything you didn't go looking for.
--> updating only from the vendor's official site.
--> configuring plugins per site.
--> setting up and properly configuring a firewall
--> setting up the system to prevent unauthorized installation of executables.
Whether the executable is a virus, trojan, or worm, doesn't really matter, if it can't intrude.
Sometimes even the "experts" can't agree what to call something. Remember Conficker?
Security Experts - Conficker Trojan Still Going Strong
W32/Conficker is a worm with multiple variants.
The Worm.Conficker.B trojan virus is a dangerous trojan virus infection affecting computer users worldwide.
What one chose to call Conficker was of no consequence to those who were properly protected.
Conficker.A was blocked by those with a properly configured firewall
Conficker.B and later variants that exploited USB were blocked by those with security in place to prevent unauthorized installation of executables.