Well, even if you are savvy, someone else may not be. If someone not savvy gets infected and an infected file is shared with you... You get infected. If they're sharing a program they wrote that needs to be atcually installed... You get infected at the root level.
To be honest that's a weak argument that makes no sense... a "non savvy" sharing an "infected" file with a "savvy" user?
That one has already been wheeled out a few times - it's not a virus...
It's actually poor article from an ill informed viewpoint which repeats a lot of the same old nonsense.
And what happens if you get the other 1 percent? Every system has flaws that can be exploited.
Yes, there is no doubt that as apple gets more popular more viruses will be written and more exploits will appear and thus be found and exploited - but it's worth noting that viruses don't require the presence of exploits to be affective. Most viruses depend on a silly user to "double click" and that's it. Once again if the user executes the virus code while logged in as a use, the code will only inherit the user permissions - it won't be able to harm the system beyond what the user does or install any system servers/init scripts. This is one of the many reasons why *nix is not a very attractive market for the virus programmers...
The danger here is to to lump "security" and viruses into one category - which has certainly been the case throughout this thread. You could indeed have the most secure system in the world, but if I send you a shell script, or "batch file" as you may call it, and tell you to log in as root and run it without inspecting it's contents, you are taking a huge leap of faith by anyone's standards. If you tried to run it without being root, you would simply get a permissions error - at the worst it might rm -rf your user's /home directory but that's it.
On the whole though I'm not sure you'd want to run a resource hungry piece of bloatware that scans every file operation, download and code execution just to prevent you from doing something stupid to your own system...?
If the number of Mac users suddenly went up to 2 million, your "secure system" would be hit on with viruses, trojans, worms, you name it. Go back to my previous links.
The number of users, i.e. the market share, is irrelevant to security... your windows pc for example is not really a target for hackers - whereas e.g. a small datacenter running 20 or so freeBSD servers for an online retail site might be.
To cut a long story short - *nix is already out there, it's exposed and it's penetration tested regularly. In the case of open source platforms such as Linux and BSD *nix, which are built from the ground up with security in mind, their code is available to everyone so they cannot rely on the *****ic "obfuscation" idea mentioned in the article. Software obfuscation is in fact used by apple to protect their proprietary formats and protocols - it's not used for "security" reasons.
Windows was never built with security at it's heart or as it's main function - windows is insecure because microsoft have made it so - it also serves to keeps the massive anti-virus / technical support eco system built around ms products humming along nicely.
The time for an anti-virus isn't after something happens, it's before. A small free one will do you good.
As a Linux user I have no need - but of the anti-virus programs I could install, most would just be wasting valuable resources scanning files for windows viruses... which I don't really care about as my machine is a desktop, not a mail/file/web server. Also seeing as I only use the official repositories to build software or build from source, I wouldn't have any files to scan...
I would say that before people assume that all OS need windows style anti-malware protection - they should think again and actually try using a non windows OS as their main OS for several months before making such sweeping statements.