If Sophos can be trusted - and as a maker of security software, that's debateable - one in five Mac computers is infected with some kind of malware.
The good news, for Mac owners at least, is that the malware most of them carry is Windows malware. Much like how a cold for birds can be a crippling illness in humans, Windows malware can lie dormant on Mac systems, only to infect Windows systems they make contact with...or that same computer if they're running an instance of Windows using bootcamp.
Now, that's not to say this isn't a problem. Computers carrying malware are an issue anywhere, no matter what the symptoms are. Just be aware of where this advice is coming from.
As Macs get more popular too, it's a good idea to think about having some sort of security software, no matter who makes it. And trust me, as Macs get more adopted, options will start popping up.
But these stories are happening more and more often and it's getting tougher to root out the real scares from the trumped up stories.
That Flashback Trojan turned out to be an exploit in Java and not a vulnerability in the Mac platform, as it was initially reported.
Security firms have an interest in scaring users into buying their products, even if a lot of the information they utilize is true.
It's just easy to get swept up in it and disregard any kind of careful eye for why someone is warning you about viruses. Mac's aren't immune, that's for sure, but they're also less susceptible to viruses by the nature of being a closed platform.
That much is still true, no matter what anyone says.