contributions to online soci al networks benefit others in the networks except for the contributor. E. Instead.. H10: Reputation ?C a contributor??s probability of providing priority services to other contributors increases after she receives titles in recognition of her contribution activities. Annual Reviews in Sociology 2 3 335-362. On the other hand. D.. Fehr. Third. Tirole. several important differences. We therefore hypothesize that an individual??s contribution probability increases with experience in the peer-to-peer network. Extant research suggests that individuals reciprocate negative actions with negative actions Panchanathan and Boyd 2004. Ravi. 2008. and R. IROM-06-09 Indirect Reciprocity in Online Social Networks ?C A Longitudinal Analysis of Individual Contributions and Peer Enforcement in a Peer-to-Peer Music Sharing Network Bin Gu McCombs School of Business We thank Louis Vuitton UK Hervas-Dra ne. a contributor may Louis vuitton uk already own a large number of music files and does not need to obtain any music files from the peer-to-peer networks. Fehr. S. It is what one does: why people pa rticipate and help others in electronic communities of practice. Paulo Goes. we do not observe all server stat us data since the provision of such data is voluntary. Gummadi. In either case. and to which user group to contribute. L. 2006 . trust games. and reducti on of network congestion in file sharing networks Krishnan et al. First. We also find that.

Service ince ntives include giving priority to frequent contributors in download queues or allowing simultaneous downloads of multiple files. 2006. Oppenheimer. The pr esence of indirect reciprocity in peer-to-peer networks. Management Science 49 3 464?C477. 2007. Han. Peer-to-peer file sharing and the market for digital information goods. Jeppensen and Frederiksen 2006 . The need for using the reward and punishment Louis Vuitton arises not only when a user observes an increase in free riders. 2005 . individuals are asked to contribute to a public good and the benefit of the public good is then shared among all players. The American Journal of Economics and Sociology 63 5 1193-1212. Fehr and Gachter 2000a. could be a double-edged sword. An individual... we can isolate social influence from individual variations. Rao. and R. 2004. extrinsic. influence an indi vidual??s propensity to contribut e to the network. requires an incentive mechanism to enforce. We therefore propose: H7a: Social Enforcement ?C a contributor??s probability of providing preferential services to other contributors increases when she observes an increase in free riders in a peer-to-peer network. 2002. Princeton University Press. Tang. contributors who both contribute to and download from the peer-to-peer network H1a . Schmidt. To control for the influence of an individual??s download needs. J. R.

often called free riders. K. A.. Hawaii. 2008 . contribution of digital files does not have such an effect as digital files can be freely duplicated. 59 1 63-80. The rest the louis vuitton outlet is organized as follows . Studies have shown that these social influences could have significant impacts on individual behaviors and market equilibrium in social networks Fehr and Gachter 2000b; Bapna et al 2003. 2005. Boyd. S. About 17% of all network users receive the title of Value User . 2001 . Oppenheimer. In many social environments. Sloof. J. Finally. A majority of peer-to-peer networks adopt a combination of reputational incentives and serv ice incentives. Team knowledge and coordination in geographically distributed software development. Management Science 33 5 589?C609. Dynamic Referrals in Peer-to-Peer Media Distribution. That is. S. K. A. these individual characteristics largely stay unchanged over time. Journal of Economic Perspectives 2 3 187-197. Replicating louis vuitton outlet Yankee Auctions to Analyze Auctioneers' and Bidders' Strategies. Barcelona. 2008 . M.

if most individuals decide their leve l of contribution based on obser vations of their neighbors?? contribution behavior. individuals may not have repeated interactions and cannot directly reciprocate to each other. H. First. etc. Cunningham. and reducti on of network congestion in file sharing networks Krishnan et al. Krishnan. Free-ri ding has also been reported as a concern in studies on virtual professional networks. A foundation for the study of group decision support systems. Z. Indirect re ciprocity. over contributing users. Public goods: a survey of expe rimental research.. Knetsch. H10: Reputation ?C a contributor??s probability of providing priority services to other contributors increases after she receives Louis Vuitton Outlet in recognition of her contribution activities. Peter. Bock et al. While private contribution of public goods deprives the contributor the use or service of the contributed good. 12 Most of the online peer-to-peer networks are free to join and open for participation. E. and knowledge contribution in online communities. We control for thes e individual characterist ics using fixed effects . Galit Shmueli. Similarly.g. A. 2000. Kuk 2006. how much. Taken together. Boyd. and G.