E-mail marketing is a form of direct marketing which uses electronic mail as a means of communicating commercial or fund raising messages to an audience. In its broadest sense, every e-mail sent to a potential or current customer could be considered e-mail marketing.
However, the term is usually used to refer to:
•  sending e-mails with the purpose of enhancing the relationship of a merchant with its current or previous customers and to encourage customer loyalty and repeat business,
•  sending e-mails with the purpose of acquiring new customers or convincing current customers to purchase something immediately,
•  adding advertisements to e-mails sent by other companies to their customers.

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