For decades, muti-level marketing companies like Amway, Mary Kay, Herbalife, Avon, and Usana have fought against being labeled as pyramid schemes. They say that pyramid schemes are illegal, and that their MLM business format is perfectly legal.
My definition of MLMs is a little nuanced. I tend to call them legalized pyramid schemes. What I mean by this is that multi-level marketing companies are indeed pyramid schemes, but our state and federal governments allow them to operate and generally call them legal if they have the right window dressing.