http://en.wikipedia.org/wiki/Protection_racketA protection racket is an extortion scheme whereby a powerful entity or individual coerces other less powerful entities or individuals to pay protection money which allegedly serves to purchase "protection" services against various external threats.
Those who do not buy into the protection plan are often targeted by criminals existing inside or outside of the organization. These crimes are typically thought to originate from the organization itself. When a business refuses to pay for protection, word is put out that they are outside of the local organization's protection (these organizations often exist in the absence of a trusted police force) and that the business in question is therefore free game for freelance criminals or the organization itself.
The protection money is typically collected by a "bag man". Although the organization might be particularly coercive in obtaining protection money, it is usually careful to shelter its "mark" from attacks by competitor organizations that similarly attempt to solicit or threaten the targeted individuals or businesses. Disputes between organizations concerning territory consequently arise from two competing predators attempting to extort from the same "clients."