Multi-level marketing (MLM) is a controversial marketing strategy in which the sales force is compensated not only for sales they generate, but also for the sales of the other salespeople that they recruit. This recruited sales force is referred to as the participant's "downline", and can provide multiple levels of compensation. Other terms used for MLM include pyramid selling, network marketing, and referral marketing. Many pyramid schemes attempt to present themselves as legitimate MLM businesses. Some sources define all MLMs as pyramid schemes, even if they are legal. MLM is illegal in mainland China. According to the U.S. Federal Trade Commission (FTC), some MLM companies constitute illegal pyramid schemes which exploit members of the organization.