from the aha! dept
It weeds out all the non-suckers.
Think about it from the scammer's point of view. With advance fee scams, they need to string along someone for a while. A live sucker can be quite valuable, but also involves quite a bit of work. So, for it to be worthwhile, they actually need exceptionally gullible people and by flat out saying they're from Nigeria, given how closely associated that country is with such scams, they quickly weed out the people who are probably smart enough to realize they're getting conned. Since the cost to them of spamming everyone is close to nothing, you may be confused about why you keep getting "Nigerian prince" emails, but they don't care about you. In fact, in ignoring those emails, you're kind of doing them a favor by not bothering them with time-consuming efforts that won't pay off.
As the WSJ piece notes, this highlights a potentially better way to deal with such scammers: waste their time. Of course, we've written about such scambaiters before, with 419 Eater being the most well known community. But this research suggests that, not only are such efforts amusing, they can be genuinely effective in harming the economics of such advance-fee frauds.