E-marketing is the concentration of all efforts in terms of adapting and developing marketing strategies into the virtual spaces: web, social media… In an e-commerce site, e-marketing must help consumers in their purchase. This requires precise knowledge of the customer´s preferences. For this reason, holders of e-shops must find out to whom, to what, how and when to refer to the customer, ergo, to know the "consumer decision journey" and strengthen their engagement. This analysis is obtained when the customer is visiting an e-shop because (s)he leaves a digital footprint that can be used to understand his/her needs, desires and demands as well as to improve web presence. These data can be used for data mining to understand the e-marketing and selling processes in a better way. In this paper a survey of 86 e-shops in Spain is presented. In the conclusions, some ideas for good emarketing practices related to the buying behaviour analysis of customers are shown. Hence, new trends in e-marketing are suggested from a strategic, tactical and operational level in which different data mining techniques ease the purchase and the engagement.