Based on what I could glean from the article,
There is a virus called MacDefender which displays a screen saying that the Apple Software has detected a virus, and do you want the system to fix/remove it?
When you give it permission, it then plays nasty with your computer.
The AppleCare rep is saying that Apple Software DOES NOT come up and say it found a virus and will fix it for you, so if you see that, you know you are infected and need to get some REAL antivirus software to fix it.
It is NOT a virus, it does not propagate itself.
ONe has to download it and allow the system to install it.
From page 2 of the article;
“EB: So customers who get hit by this are installing it and giving their admin password?
AC: Yes.
EB: if they stop before that, nothing bad happens?
AC: Yes, the file will download but for it to install it requres the password. it tries to trick you into giving it by saying its required to remove the infections.
EB: Ah yes, social engineering.
AC: Indeed, looks rather real, if you ignore the fact it pops up in your browser… but for most of us that know computers that’s a giveaway there.”
Don’t give out your password!