You then print and mail out as many as you can, hoping others will do the same as you. The letters are liberally sprinkled with references to how much money you will make, and how many people are sure to participate. Pyramid schemes are what chain letters are based on. You buy into one, then you need to recruit others below you, to move you up the line. The people you recruit, in turn, need to recruit others, and so on.
Pyramids go by all kinds of names and formats.
That makes you a passenger. When you recruit 8 more people, you become a stewardess. Your 8 people then need to recruit 8 more, to move you up, and so on. You're promised that you will get hundreds of dollars when you're the pilot. These programs all share many characteristics.