Technically speaking, pyramiding is an illegal practice of a company that solicits their members to recruit more members, more than selling the product. In turn, the primary source of income for its members is the number of members they have recruited instead of the products they have sold over time. Clearly, not all MLMs are pyramid schemes, but it all seems like a matter of degree.
MLMs have been made illegal in some jurisdictions as a mere variation of the traditional pyramid scheme, including in mainland China. In jurisdictions where MLMs have not been made illegal, many illegal pyramid schemes attempt to present themselves as MLM businesses. Given that the overwhelming majority of MLM participants cannot realistically make a net profit, let alone a significant net profit, but instead overwhelmingly operate at net losses, some sources have defined all MLMs as a type of pyramid scheme, even if they have not been made illegal like traditional pyramid schemes through legislative statutes.