The Situation Lens: A Metaphor for Personal Task Management on Mobile Devices

In this paper we discuss personal data management with mobile devices, an activity requiring the composition of services offered by standard suites of applications. We propose a data model and an interface model that allows users to define activities, tasks and services, to navigate among them according to the evolution of the personal situation as perceived and interpreted by the users themselves. The interface model acts as a lens exploring the situation, zooming into the details, covering different areas of the personal data, supporting the user in the role of a composer of personal services.