A current open issue in the Human-Computer Interaction research area is the study of applications that can work in the Social Web environment. This paper presents a persuasive web application for sport and health, designed to motivate people in their exercising activity. For the first time ever, our application makes available on a web browser some features previously available only through a mobile application. Moreover, it allows a richer interaction with the Facebook social network. This work shows how linking Human-Computer Interaction with the Social Web can be exploited, to improve the motivation of users to a more active lifestyle. This is done by providing an improved user experience, through the targeting of new types of devices and new communication networks.