When I was growing up, my parents got drawn in by loads of these, they wasted, time, energy and effort on what were basically scams. If these people have such great products, why don't they market them through, you know, shops?
Someone I don't know very well on FB (not an MNer!) sent out a long email to lots of people full of MLM shite talk, and I am v tempted to answer back talking about how much money and time my parents wasted on this sort of bullshit, all for nothing.
(Yes, I know some people make some money with Avon, and maybe Amway (Amway is still very evil). But I still hate them, for the scamminess, for the 'pester your friends' sales techniques, and for the flagrant smell of bullshit that permeates everything about them.)