Purchasing decisions do not always come from the rational mental processes but are often being driven by emotions. This insight made researchers think of emotions as of an essential contextual variable capable of enhancing personalized services and providing more precise recommendations within e-Commerce. In this paper we explore the studies made to discover why emotions are an important research domain necessary to understand the purchasing behavior of online shoppers. We also explore how user emotions can be captured and recognized by existing technologies to provide enhanced personalization. Specifically, we apply Webster and Watson (2002) literature review approach to create a sample of studies published in scientific journals and conference proceedings. We synthesize the extant studies on the role of user emotions for personalized services within e-Commerce. We also provide a comprehensive concept-matrix which aggregates the range of existing emotions recognition technologies and highlights which specific emotions these technologies are able to recognize as well as in which domains these solutions are applied. Our study extends prior reviews and provides insights into open research areas which will benefit Human-Computer Interactions (HCI) practitioners and researchers in academia and industry.