One of the interesting features about markets is that they are rife with things that are only true if lots of people disbelieve them. For example, markets will only be efficient (and indexing therefore your best strategy) if lots of people believe that they are inefficient, and thereby help set the price by buying and selling individual stocks.

The same thing, it strikes me, is true of the much vaunted security of Macs. Macs don't get spyware and viruses, but that's not because their security is so much better; it's because so few people use them that it doesn't pay to build spyware and viruses for them. However, if everyone really believed that Macs were much safer, more people would use them, and then it would pay to develop malware that targets them.

Apparently it may be changing anyway, as Apple gains some market share, and Windows security gets better. Sigh. I can't say I miss my Norton antivirus.