Lol MLM is just a system, Multi level Marketing, it is just a scheme to maximize someone's profit.  Depends on where it is being used is the problem.  Some company offers leveraging in order to make their client earn profit from buying their products and earn from those they had referred to the company.  If there is products which has equivalent value to the price they had paid is given and the bonuses depends on the tangible stuff that is bought by their referred buyer, then the system cannot be called a scam.  It is HYIP's and ponzi scheme that is scam.