Online marketing is an integral part of e-commerce nowadays and includes many different ways of company's presentation, such as e-mail marketing, content marketing, social media, affiliate marketing and so on. The aim of the article is to highlight the importance of e-mail marketing due to the fact, it is considered as one of the most effective communication tools. The part of the article are also fundamental metrics used in e-mail marketing such as delivery rate, open rate and click through rate. In the end of the article are recommendations and suggestions for creating of successful e-mail. The eyetracking technology was also used to analyze the gaze of Internet users at mailbox.