Mobile crowdsensing (MCS) enables collective data harvesting actions by coordinating citizens willing to contribute data collected via their sensor-rich smartphones that represent sources of valuable sensing information in urban environments nowadays. One of the biggest challenges in a real long-running MCS system lies in the capacity not only to attract new volunteers, but also, and most importantly, to leverage existing social ties between volunteers to keep them involved to build long-lasting MCS communities. In addition, the advent of high-performing devices and ad hoc communication technologies can help to further amplify the effect of sensing actions in proximity of the volunteer devices. This article originally describes how to explo...