No really it is. In a "pyramid Scheme" all the money goes to the top. you start out at the bottom and a SINGLE person at the top gets the money.
turn the triangle upside down, Everyone benefits. like this:
You are selling product "x".
you get three members under you and teach them how to sell product "x" which you get a slight commision off of each sale THROUGH the company, not the salesman.
those three teach three each how to sell product "x". you get a small comission off of each sale and each new member recruited.
now this only goes so far down the chain with some companies. so you will have to "re-sow" a crop everyonce in a while when it becomes barren (inactive).
hopefully this explains it a little better:

it truly is legit. Almost everything becomes a tax write off as long as it has something to do with the business.