The ad doesn’t explicitly state there are no viruses for Mac but it certainly suggests there are closer to 0 than than 114,000. The ad was probably true back in 2006. It very possibly still is true.
However, what really bothered me is that the ad made light of a very serious issue. An issue that disproportionately affected PCs because there were more PCs. In other words, PCs (Windows actually) provided a larger audience for virus/malware developers to target thus PCs were a more desirable target.
Today I believe Mac’s popularity is increasing due to the popularity of the iPhone. I also believe that means the Mac becoming increasing popular among viruses and malware developers.
Success begets attention (positive and negative).
Ultimately, I’m not trying to argue whether PCs/Windows are or were more or less resilient to viruses/malware than Macs/OS X. I’m only pointing out that security is a serious challenge we all face as software engineers. Do not make fun of other’s security issues. One day, should your software become popular, you will be under attack as well.
Respect the problem.