Lessons learned from the design, implementation, and management of a smartphone-based crowdsourcing system

Ubiquitousness of smartphones, when combined with the power of crowdsourcing, enables radically novel application scenarios, where a massive amount of mobile users scattered over wide geographical regions cooperate towards a single goal. Nevertheless these new possibilities come at the cost of additional complexity, such as the presence of humans in the control loop, scarce resources of mobile devices, increased management costs due the large number of users. In this paper we report and discuss the lessons learned from the design, implementation and management of Portolan, a smartphone-based crowdsourcing system aimed at monitoring large-scale networks.