AHA!!!
>> I find it hard to believe that over 1/2 million Mac users would go to those sites.
I don't.
In fact I guarantee you that if there are porn videos streaming out of Scandinavia, Denmark, etc. from those sites, then there are AT LEAST half a million Mac users, out of 75 million total Mac users, who would have hit those sites sometime in the past few months. And if many or most of those became infected...
Many of the U.S.-based porn sites redirect the user to an offshore site or server -- the stuff that comes out of Europe is often a lot more explicit than what's allowed in the U.S.
This could indeed explain the numbers -- IF the numbers are true, which has yet to be established.
Still have to account for the very low number of actual user complaints. Although that could be explained if the ONLY way to get infected was to visit some super-raunchy porn site, and nobody wants to admit to that... LOL!
I have now scanned through several hundred user comments on places like ZDNet, MacDailyNews, CNet, MacSurfer, etc., and have found exactly TWO users who have claimed to have been infected with the Flashback Trojan, and frankly both of them were very suspect comments... replete with typical troll like word usage, including reporting that "My MAC was infected!" Note the use of all caps to name his computer. The other claimed to have bought his because of the "I'm a PC... I'm a Mac" commercials claims that Macs never got viruses... and how disappointed he is now that he "finds his Mac is infected with a virus!" and that his next computer is going to be a Windows 8 computer. LOL!
Others are starting to comment on the dearth of reports of infected Macs being seen on forums. They JUST AREN'T THERE!
Here is a website with a script that you can run that will easily check your Macs for the presence of the Flashback Trojan... no terminal and cutting and pasting of the commands:
Site with Flashback checking script
Just downloaded and run it from the script editor.