PCs and viruses
As a dyed-in-the-wool Mac users, I live a sheltered life largely free of troubles like worms, viruses, trojan horses and the like. I'm certainly impacted by them -- my deleted items e-mail folder chock-full of "My Details," "Your Details," "Wicked Screensaver" and the like, all culled to the wastebin thanks to a rules filter of my own creation. But in terms of actual infection, I really don't have to worry that much -- the Mac has never been much of a magnet for virus authors, and Mac OS X even less so.
Security through obscurity has been offered as one explanation -- with few enough Mac users out there, it's said, virus writers don't have much of a reason -- or much experience -- writing code that can affect Macs. Others offer the innate security of Unix-based systems (like Mac OS X) as another reason. I suspect that the truth lies somewhere between these rationales.
The Boston Globe ran an article about the issue of virus protection, and tapped on yet another explanation of why Windows users are so affected by this issue: Because it's so damn tough (and, in some cases, expensive) to keep your system up-to-date with all the patches and security you need to.
Not only do you get conflicting, weird, and unfriendly messages when you try to apply patches, but you have to pay companies like Symantec subscription-based fees to keep your virus protection software current. It's enough to make many casual users shirk their responsibilities. I suspect that small businesses are probably a bit better about this: I can't imagine a more ignominious way to piss off your clientele than to send them worm-infected e-mail, except maybe to lose control of bodily functions on them in a face-to-face meeting.
The inconvenience of upgrading has largely been my (admittedly limited) experience with PC use too. The last time I had a PC, I spent much of the first four or five hours of use downloading and applying system patches to Windows XP -- through a broadband Internet connection. This was a huge contrast to the relatively quick and painless series of high-speed upgrades managed through my Mac OS X v10.2-equipped Mac, which took all of about 20 minutes to apply.
The worst, however, was the limited-time version of Symantec's anti-virus protection software that was included. Every time I booted the system I was reminded that I only had a few days to register and pay for the subscription before my anti-virus software would deactivate itself. I hated the idea of being held hostage this way, and never ended up buying the upgrade, obviously.
By comparison, Mac users have it pretty easy -- not only do we have only an infinitesimal fraction of Mac-native viruses and related problems to worry about, but virus protection software is pretty cheap and easy to come by. I use Virex, which I got for free as part of my $99 annual .Mac membership, and it upgrades itself every month without asking for another dime. There are other Mac-based virus software packages that similarly ask for one registration fee up front but don't charge you again.
No scary messages for any of this stuff either. The Apple-made system updates only come one way -- through the Software Update system preference pane -- so you can trust their pedigree with reasonable assurance.