As Macs become more popular, they become more of a target for hackers (old-school bragging rights and new-style theft both go best with a big pool of targets), but Apple's dismissal of the Oompa Loompa trojan reminded me of the old joke about the Unix virus (read the mail, forward the instructions to a friend and then format your hard drive): they say it "requires a user to download the application and execute the resulting file".