Crowdsourced content sharing has become a fast-growing activity in today’s online social networks, where such contents of interest as instance video clips are created by diverse source users and conveyed over the network as friends view and reshare. The rapid and boundless propagation in a mobile crowd however often creates severe bottlenecks on the server side and incurs significant energy and monetary costs on the mobile side, particularly with the still expensive 3G/4G cellular connections. This paper presents SoCrowd, a novel framework for large-scale content sharing in a mobile crowd by exploiting contacts, i.e., users happen to move close with such short range low power communications as WiFi and bluetooth being enabled. We show strong evidence that the contacts widely exist in realworld mobile crowds, which have great potentials for traffic offloading. We present optimal solutions for the single source propagation in a mobile crowd with contacts, which is further extended to accommodate crowd sources in practical settings. The effectiveness of SoCrowd has been demonstrate by extensive simulations driven by realworld traces and datasets.