Following the BackSpin column Darwin and spam, I got a fair amount of feedback. Reader Brian Fahrenheit (a pseudonym because, he claims, his letters get him in hot water) wrote: "Your article on spam eradication states all attempts to kill spammers actually contribute to their survival. This curious phrasing of Darwin's thesis is correct if spammers have the means to adapt to all eradication attempts."

Correct, I did contend that attempts at getting rid of spammers contribute to their survival but it is their survival collectively, not individually. This leads to Fahrenheit's second statement that my phrasing of Darwin's thesis is "curious." Darwinian evolution is inherent in all systems of imperfectly replicating discrete entities that compete for resources in a shared finite environment.

Consider frogs breeding happily in a stream. One day arsenic leaches into the water. Some frogs are very sensitive and die off producing no offspring, while less sensitive ones manage to produce a few offspring before they die.

For a while the reproduction rate of frogs is low, but the imperfect copying mechanism eventually produces frogs that can tolerate arsenic. The new version of the frogs starts to reproduce at a greater rate than the poorly tolerant ones, and in a few generations their duplication instructions, their genome, becomes dominant. Eventually only arsenic-tolerant frogs will be in the stream.

The same principles apply to spammers: Given low doses of arsenic ... er, sorry, being whacked out of existence by laws, a few spammers eventually will appear that are capable of surviving those laws.

Reader Bob Moulton pointed out that the same "principle applies to ... digital rights management copy protection. We're just breeding a better species of crackers. Witness the Starforce protection scheme, which was cracked the day after it was released."

You might argue that because human brains full of ideas, emotions and a desire to drink tea are involved, Darwinian forces don't apply, but just consider: Most of the guys who run the biggest corporations in the world aren't Einsteins. That's not to say they aren't really smart, just that they aren't the smartest folks out there, but they are the best adapted to running corporations.