“I was in a religious cult in my youth—so I quickly recognized the feeling,” says Charlotte over a confidential internet call from Australia. She does not want to divulge her full name because, she says, the subjects of this discussion are highly litigious. Charlotte is part of the Anti-MLM Coalition—a group of activists striving to educate people about multi-level marketing. Also known as network marketing, multi-level marketing is a business model—popularized by the likes of Avon and Tupperware in the middle of the last century—under which a brand’s products are sold through a network of unsalaried representatives. The representatives buy discounted stock to resell and are remunerated through a system of commissions on their transactions and those of anyone they enlist a...