Spam subject lines mutate like viruses. What was Viagra last week is vIaGrA yesterday, and will become V!@6Ra tomorrow. A little blue pill by any other name . . .

Fortunately, online communities are finding ways to protect themselves — a great example of grass-roots Internet inoculation.

Brian Hayes of The American Scientist explains:

The spam we see today is shaped in many ways by our own efforts to combat it . . . the contest is between a host organism and pathogens or parasites, and where both sides have to adapt and evolve in order to survive. In the case of bacteria and viruses, the vast majority never make it, but nature is profligate and can afford such high attrition; likewise spammers find it worth their while to send a million e-mails for a handful of responses.

Perhaps this heralds the end of annoying new media mass marketing.