Right it is a Nigerian scam variation and since he used a Yahoo email address Yahoo will delete the account, I missed that it was a Yahoo account the first time I read you message. It will take him about 30 seconds to create a new email account and send more scam mail. Yahoo won't do anything if the email isn't from a Yahoo account, even if it is to a Yahoo account beyond letting you tag the email. The problem is that he has a way to spam WayMarking. Once one of the spammers hits a site the rest will follow since they are all getting their software tools from a supplier that automates the process for them. You can buy a how to spam kit in Nigeria and go to a boiler room and pay to sit at their computers and use their tools.