Although we have talked briefly about chain letters in pyramid schemes, I think that chain letters are slightly different.
Chain letters are a type of pyramid scheme.
Almost everyday that I am marketing, I find a chain letter in my email in-box. My Mom and I got a chain letter in the mail. I won't bore you with the details, but of course did not work. Not only do chain letters not work, they are illegal. You are not exchanging a real product or service.