Chain Letter

Chain letters typically contain a list of names and addresses (or accounts), instruct the recipient to send a small amount of money or a gift to each name on the list, remove the oldest name and add their own, and then send copies to a set number of new recipients. The implied promise is that as the letter circulates, the recipient's name will rise to the top and thousands of people will send them money.

The mathematics of chain letters are fatally flawed. For everyone on a list of, say, five names to profit, the scheme requires a geometrically expanding pool of participants that quickly exceeds the world's population. In practice nearly every participant pays in and receives nothing back.

Email and social media have given chain letters new reach, with digital variants promising everything from cash to good luck. Most countries classify chain letters that involve cash transfers as illegal lotteries or pyramid schemes, and postal fraud laws apply to physical versions.