>>  The 419 Scams 

A Five Billion US$ (as of 1996, much more now) worldwide Scam which has run since the early 1980's under Successive Governments of Nigeria. It is also referred to as "Advance Fee Fraud", "419 Fraud"  and "The Nigerian Connection". The number "419" refers to the article of the Nigerian Criminal Code (dealing with fraud. This scam usually begins with a letter or e-mail purportedly sent to a selected recipient but actually sent to many, making an offer that would result in a large payoff for the victim. The e-mail's subject line often says something like "From the desk of Mr. [Name]", "Your assistance is needed", and so on. The details vary, but the usual story is that a person, often a government or bank employee, knows of a large amount of unclaimed money or gold which he cannot access directly, usually because he has no right to it. The million dollar worth property might be claimed to belong to a terminally ill wealthy person with no relatives or a wealthy foreigner who deposited money in the bank just before dying in a plane crash (leaving no will or known next of kin) a US soldier who has stumbled upon a hidden cache of gold in Iraq, a business being audited by the government, a disgruntled worker or corrupt government official who has embezzled funds, a refugee, and similar characters. The investor is promised a large share, typically ten to forty percent, if they assist the scam character in retrieving the money. Whilst the vast majority of recipients do not respond to these e-mails, a very small percentage do, enough to make the fraud worthwhile as many millions of messages can be sent. Invariably sums of money which are substantial, but very much smaller than the promised profits, are said to be required in advance for bribes, fees, etc.—this is the money being stolen from the victim, who thinks he or she is investing to make a huge profit.

The range of topic of these scams can vary from romantic scams, hitman (threatening), goods and services offer, baby sitting, check cashing, lottery, bomb scams,  charity, craiglist (online classified add networking site), scam recovery scam(!!) and what not!!!

As someone described this business aptly - "The availability of e-mail helped to transform a local form of fraud into one of Nigeria's most important export industries."

(Disclaimer: the above is NOT my own writing, I have used many open source resources as it is for composing this piece of information. Please don't bug me with copyright issues!!)