It's unfortunate, but there are people on-line who do nothing but gather addresses. They are paid for each fresh one they dig up. Those lists are then used by scammers to mass e-mail, hoping someone will bite on thier scam.
The others pop up in chat rooms, on dating sites and message boards.....most are looking for one thing. Someone to scam. Seems that if they pish long enough, someone will eventually fall for thier sob story and start handing out the cash.
One reason so many are from Nigaria is our laws dont effect them, they are out of reach. They also have the idea, or so it seems, that Americans are all rich and stupid !
Ill almost lay you odds that if you are chatting up someone on line who is looking for money, you wont be the only one he/she is telling the same stories.
All you really can do is protect yourself. If it seems a bit "odd" in some way..either in e-mail or in person...run, dont walk !
BJ