Science of Networks in Communities (SONIC), Department of Industrial Engineering and Management Sciences, Northwestern University, Evanston, Illinois 60208
Peer-to-peer sharing networks have seen explosive growth recently. In these networks, sharing files is completely voluntary, and there is no financial reward for users to contribute. However, many users continue to share despite the massive free-riding by others. Using a large-scale data set of individual activities in a peer-topeer music-sharing network, we seek to understand users' continued-sharing behavior as a private contribution to a public good. We find that the more benefit users "get from" the network, in the form of downloads, browses, and searches, the more likely they are to continue sharing. Also, the more value users "give to" the network, in the form of downloads by other users and recognition by the network, the more likely they are to continue sharing. Moreover, our findings suggest that, overall, "getting from" is a stronger force for the continued-sharing decision than "giving to."