From a functional perspective, wrist-worn fitness sensors collect physical activity metrics by estimating steps based on arm movements, and wirelessly transmit data to the Internet where they are aggregated, and displayed by specially designed software programmes. As a result of this division between physical (wristband) and digital (software and data) artefacts, the transition between its components should be seamless (Hindman, 2015). In fact, wearable devices deliver the promised functionality when all their components (sensor, data, and software) work well together as a cohesive information system that can be seamlessly inserted into the personal technology portfolio (Fernando, 2015). From a lifestyle perspective, wearable devices are successful when they are easily integrated into everyday activities(Vella,2013),andachievetheultimategoalfor which quantification of physical movement is required, such as lose weight, or improve fitness (Patel, Asch, & Volpp, 2015). We propose that a necessary condition fortheusertoachievetheeffectsofself-quantificationis her ability to interact with all components of the wearable information system. Furthermore, we argue that minimalist wearables, where the physical device lacks screen and buttons, are discreet to wear but present usability challenges, as users must figure out how to operate them without any clues. Even if effortlessinteraction is achieved,the data collected by the device must be meaningful for the user to achieve their lifestyle improvement goals (Fernando, 2015; Vella,2013). To examine how regular users integrate minimalist fitness trackers into their lives, this study adopts an affordance lens based on the mediated-action perspective of Activity Theory (AT). It proposes an adaptation of the affordance framework originally developed by Kaptelinin and Nardi (2012) and applies to a sample of online user reviews collected during the initial 15-month period after launch of a popular minimalist fitness tracker (Fitbit Flex). In addition to offering insights on how everyday users embrace minimalist wearables, this research also expands the conceptual and empirical boundaries of AT in Information Systems, with the concept of affordances and the use of online reviews (ie, user-generated content) as data. The remainder of this paper is structured as follows. The next section presents the theoretical background and the adaptation of the affordance framework. The following section explains the research methods, sample, and data analysis. After describing the results and the statistical analyses, the paper closes with discussion, implications for theory and practice, and concluding thoughts.