SUMMARY
In this paper we investigate collaborative learning that takes place in a city with the support of mobile and wireless technology. Based on a literature review, we identify and discuss four main roles that technology can play in supporting (1) performance of shared tasks, (2) social networking, (3) active participation, and (4) visibility of learning. We claim that the full potential of new technology emerges by supporting learning that comes from exploration, interaction, and serendipity. Realizing this potential raises a number of technical challenges that are still largely unexplored. In particular, we claim that there is a need to move from applications design to a service-oriented infrastructure that eases the development and adaptation of applications for multiple and interleaved learning experiences. Services that are common across different learning scenarios and can be used as building blocks need to be identified. The aforementioned roles are the first step towards this direction.