Sparrowvsrevolution writes "Four years ago, security researcher Adam J. O'Donnell used game theory to predict in a paper for IEEE Security and Privacy when malware authors would start targeting Macs. Based on some rough assumptions and a little algebra, he found that it would only become profitable to target Apple's population of users when they reached 16% market share. So why are we now seeing mass attacks on Macs like the Flashback trojan when Apple only has 11% market share? O'Donnell says it turns out he may have underestimated the effectiveness of the antivirus used by most Windows users, which now makes overconfident Mac users a relatively vulnerable and much more appealing target. Based on current antivirus detection rates, O'Donnell's equations now show that victimizing Macs becomes a profitable alternative to PCs at just 6.5% market share."