Consumer is a person who buys products for its personal usage. Consumers play a vital role in the economic system of a nation. Without the consumers there would be no need to produce or to sell products. Consumers are protected by law against any kind of malversations. A Customer List is a list of previous buyers from a company. The list is maintained in order to continue the business relationship, keep up with buyers and to promote customer loyalty.In the context of social systems, consumer represents a person or organization that uses certain service or product. In economics and marketing, consumer is a purchaser of goods or services. In the chain of distribution, consumers play crucial role, since without consumer demand, producers would not have the motive for production. In this context, there is also a term alpha consumer, which can be defined as a person who stands behind the concept of the product, and who then adopts and validates the product. In legal and political register, the term consumer denotes a living person, as opposed to corporations or commercial users. From the aspect of biology, more precisely the food chain, consumers are organisms that eat, or consume in some other manner, other organisms in order to gain energy. One whole ideology and socio-economic order called consumerism, that emerged in 20th century, is derived from the term ‘consumer’.