Here's an interesting story: "Gartner: Beware of Mac OS spyware | CNET News.com". Given that there are absolutely no viruses for OS X at this point in time (compared with the 60,000 + out there for Windows) one has to wonder what prompted this FUD.
Oddly, this comes right after Symantec warned about Mac's OS X becoming a target for hackers and viruses (again despite the fact that there isn't a single documented virus for OS X).
So why all the concern about something that doesn't exist? For Symantec, a company that sells anti-virus apps for Mac (again, despite the fact that there aren't any documented viruses for OS X) this is especially troublesome.
I suppose that Windows users ought to be extremely concerned that someone could invent a virus that will spread from machine to machine, overcome all known security mechanisms, erase all their data, and render their machines unusable forever. It's about as likely as non-existent Mac OS X viruses and spyware running rampant.