E-mail marketing is a practical form of direct marketing which uses email as a means of communicating commercial or fundraising messages to an target audience. In its broadest sense, every email sent to a potential customer can be considered email marketing. However, the term is largely used to refer to:
Sending e-mails with the goal of getting new customers or convincing old customers to buy what is offered.
Adding advertisements in emails sent by other companies to their customers, such as newsletters or special offers.