Zero Plus Infratech | E-mail marketing has become an essential tool for business ever since the introduction of the Internet to the world, however, some campaigns that make it through to our inboxes are absolute rubbish that we don't take any notice of. This article seeks to explain what email marketing really is, why companies should use it and how they should go about doing so. Zero Plus Infratech | E-mail marketing is a form of direct marketing that uses electronic mail as a means of communicating commercial or fundraising messages to an audience. In its broadest sense, every email sent to a potential or current customer could be considered email marketing.