A pyramid scheme is a business model that recruits members via a promise of payments or services for enrolling others into the scheme, rather than supplying investments or sale of products or services. As recruiting multiplies, recruiting becomes quickly impossible, and most members are unable to profit; as such, pyramid schemes are unsustainable and often illegal. Pyramid schemes have existed for at least a century in different guises. Some multi-level marketing plans have been classified as pyramid schemes. SOURCE: https://en.wikipedia.org/wiki/Pyramid_scheme
In a pyramid scheme, an organization compels individuals who wish to join to make a payment. In exchange, the organization promises its new members a share of the money taken from every additional member that they recruit. The directors of the organization (those at the top of the pyramid) also receive a share of these payments. For the directors, the scheme is potentially lucrative—whether or not they do any work, the organization's membership has a strong incentive to continue recruiting and funneling money to the top of the pyramid. SOURCE: https://en.wikipedia.org/wiki/Pyramid_scheme