Flutterby™! : Why are they from Nigeria?

Why do Nigerian Scammers Say They are from Nigeria? by Cormac Herley, Microsoft Research (PDF). Slate article on the paper. MeFi entry.

This allows us to view the attacker’s problem as a binary classification. The most profitable strategy requires accurately distinguishing viable from non-viable users, and balancing the relative costs of true and false positives. We show that as victim density decreases the fraction of viable users than can be profitably attacked drops dramatically. For example, a 10× reduction in density can produce a 1000× reduction in the number of victims found. At very low victim densities the attacker faces a seemingly intractable Catch-22: unless he can distinguish viable from non-viable users with great accuracy the attacker cannot find enough victims to be profitable. However, only by finding large numbers of victims can he learn how to accurately distinguish the two.

In other words: It costs to lead people on, so if you can easily filter for the gullible people by making your approach obviously stupid to the smart people, you quickly winnow your list.

See also: Advertisers supporting idiotic television shows in order to find gullible customers.