If you type "Nigerian" into Google, one of the top suggestions for completing the phrase is "scam." We all get them: unsolicited emails promising us a share of some lost fortune sequestered in an obscure place, if only we will help the rightful owner recover it. The "help" usually consists of transferring money to someone you don't know, most commonly in Nigeria or another African country. And, of course, the vast payout never materializes.

It should be a familiar story. In 2006, the New Yorker...