We describe findings from a deployment of a self-tracking pervasive fitness system for adolescents, and contrast it to a social version of the same system (StepStream). Overall, students in this study did not improve their attitudes about health and fitness, and there was no overall increase in daily physical activity. We provide evidence for two contributing factors: the specific social structure of the participant group, and the persuasive design of the system. Our results show that even a group with strong social ties will not necessarily leverage those connections for fitness without encouragement from the system. This study also provides evidence that attitude and behavior change seen in other deployments (especially the ‘social’ version of StepStream) are also due to these factors, and not merely the result of novelty effects or researcher bias.