Self-tracking devices and applications have become popular in recent years and changed user behaviour. Previous research has primarily focused on the adoption of self-tracking devices and their effects on self-assessment. As adoption increases, user engagement becomes prominent for the continuous use of the devices and the applications. In this study, we focus on user engagement with activity tracking applications, e.g., Fitbit Flex and Jawbone Up that offer data on user performance. We collected data from semi-structured interviews with 54 participants. We propose a process model comprising four stages which involve distinct user interactions with data: review, react, reflect, and respond. We advance research in this domain by the proposed process model that explicates user engagement in two cases: when the user encounters satisfactory or unsatisfactory results. In the latter case, we depict four response tactics when users are confronted with unsatisfactory results.

The introduction of smartphones and the accompanying profusion of mobile data services have had a profound effect on individuals’ lives. One of the most influential service categories is location-based services (LBS). Based on insights from behavioural decision-making, a conceptual framework is developed to analyse individuals’ decisions to use LBS, focusing on the cognitive processes involved in the decision-making. Our research is based on two studies. First, we investigate the use of LBS through semi-structured interviews of smartphone users. Second, we explore daily LBS use through a study based on diaries. The findings highlight that the decision to use LBS can be described by either a comparative mode based on the value of LBS in relation to other available options, or an intuitive mode in which past experiences trigger the use of heuristics. These modes in turn have positive influences on the continuance of LBS use and indicate changes in individuals’ information retrieval behaviours in everyday life. In particular, the distinct value dimension of LBS in specific contexts of use changes individuals’ behaviours towards accessing location-related information.

Despite widespread proliferation of mobile devices providing access to a variety of advanced and data-rich services, adoption of those services remains low in most of the Western world. Thus, research related to the acceptance and use of mobile technology and services continues to develop. Traditional research in this domain has been useful for exploring adoption and use related to individual technologies or novel services. However, our research efforts indicate that users often reflect on former experiences with similar technologies or services when choosing mobile services. This suggests that when exploring mobile service usage decisions, focus cannot be placed on mobile services alone. Through two longitudinal field studies conducted in Denmark during 2004 and 2005, this article further explores the manner in which users' choices of mobile services are influenced by their reference situations and reference prices. The article suggests that users cognitive referencing is an influential factor that must be considered when exploring their usage behaviour in the mobile services market.