The purpose of the paper is to identify the nature of the influence of a company’s marketing communication of the actual consumer behaviour. To achieve this purpose, the paper is structures in two parts; firstly, the recent literature regarding relationship marketing paradigm is reviewed and the value chain concept is presented. The second part contains a survey-based research which uses book-store customers as target unit. Sales promotion and advertising are used as input variables in identifying the variation in the client’s buying behaviour. Client behaviour was measured through three variables: monetary value spent by the clients within their last purchasing experience, buying frequency of the clients, and their buying intention.