Here's a modern-day question: Why are Nigerian con-man emails so obvious?
Because that makes sure only stupid people will respond to them, says Microsoft security analyst Cormac Herley in a newly released research paper.
"Far-fetched tales of West African riches strike most as comical," Herley writes in the introduction to his paper. "Our analysis suggests that is an advantage to the attacker, not a disadvantage."
When you get an email from a Mrs. Naomi Oingoboingo asking you to help her recover the millions of dollars her late husband, a Nigerian general, stashed away in secret Swiss bank accounts, you're probably going to laugh.
If the email's really ridiculous, you might forward it to your friends or post it on your Facebook page.
But even if 99 percent of the thousands of people who receive the email ignore it, that still leaves quite a lot of sad suckers who are taken in by the tale.
And, reasons Herley, if those people are dumb enough to believe such a silly story, or ignorant enough to have not heard a decade's worth of Nigerian email jokes, then they're quite likely to fall for the old-fashioned "advance fee" con that the email sets up.
The more ridiculous the email, Herley explains, the less time the scammers have to waste trying to persuade greedy individuals who will quickly see through the scheme — " false positives " from a security analyst's point of view.
"The Nigerian scammer has an overriding need to reduce false positives," writes Hurley. "By sending an email that repels all but the most gullible, the scammer gets the most promising marks to self-select, and tilts the true- to false-positive ratio in his favor."