Yeah, these folks have defiled a bunch of stuff.
To me the interesting thing is just how inept these scammers are. But the FTC says that Americans sank $1.4 billion (yea, with a "B") into 419 scams last year.
It is one of the largest foreign exchange "earners" of Nigeria and the Nigerian government, or members of same, are deeply implicated. (It is the most corrupt and dysfunctional place I know of, although it has a lot of competition, almost all of it also in Africa).
The reason that Nigerian authorities (or Cote D'Ivoire, Mali, Burkina Faso, etc). don't cooperate in squelching these scams is simple -- they are in on them.
d.o.l.
Criminal Number 18F
It's also probably a significant portion of the GNP...