Their probability of contribution increases significantly with the number of mixed contributors. governance and the viability of hybrid forms in open source software development. J. and R. Nowak and Sigm und 1998. 1998. Individuals vary significantly in their motivation and preposition in contributing to peer-to-peer networks. Oosterbeek. Oosterbeek. In sum. The de lay from congestion and the associated opportunity costs are one of the main costs incurred by individuals downloading files in such networks. Why should i sh are? Examining knowledge contribution in electronic networks of practice. The use of panel data addresses a number of challenges that earlier researchers face in cross-sectional analysis. The results also provide support for all the hypotheses. 1998. Reciprocal behavior has l ong been observed in human so ciety Ekeh 1974. B. In the context of peer-to-peer sharing networks. The American Journal Louis vuitton Economics and Sociology 63 5 1193-1212. 2003. 1996. For example. 1987. R. career opportunities Hann et al. The assumption. Kraut. it takes time for network users to learn the mechanism. Kandori 1992 suggests that private contributi ons can be maintained among self-interest indi Louis vuitton handbags uk if ??not only are deviators from the desired behavior punished. The percentage is higher than the percentage of all contributors. a proposer receives an endowment and then sends a portion of the endowment to a responder. and moral hazard. leading to a ch ain effect. Krishnan. J. Third. The rest the paper is organized as follows . Asvanund et al.A. NV. however. These motivations include reputation Wasko and Faraj 2005 . we have little knowledge on how individuals perceive the social environment and how such perception aff ects their behavior. 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. contribution behaviors are reciprocal in nature. the individual will have no incentive to contribute if she has no download needs or there is no congestion in the network. Nowak. Studies show that one determining factor for indirect reciprocity is the availability of information about cooperation level of other participants in the group Brandt and Sigmund 2005. The tragedy of the commons. Information Systems Research 18 1 42-67. Another important finding of the paper is that an individual??s probability of contribution increases significantly with her experience with the peer-to-peer network H3 .. Open source software and the ??private-collective?? innovation Louis Vuitton UK Issues for organization science. 1990. the individual will have no incentive to contribute if she has no download needs or there is no congestion in the network. American Economic Review 83 5 1281-1302. The experi ment shows that individuals have inherent incentive to contribute to public goods. We describe data and measures afterward. how much. extrinsic. G. We focus on a particular type of motivating factor ?C indirect reciprocity ?C in this study. the concept of reciprocity goes beyon d direct one-to-one interacti ons. Our analysis also has sheds lights on individual motivations of enforcing social norms in social networks. Sharpe.. R. We also find that network users respond differe ntly to different contributor groups. our results suggest that indirect reciprocity plays a pivotal role in motivating and sustaining individual contributions to online communities.. or pirated contents. contributors who both contribute to and download from the peer-to-peer network H1a . which provide incentives to network users to become free-riders in the network. Falking et al 2002 . 2005. Gribble. and S. The second set identifies individuals?? incentive to enforce social norms by punishing free riders and rewarding contributors. Herbsleb. Table 2 shows the correlation matrix for the key variables. We also find that individuals with high download needs tend to increase their contribution probability when they face more network congestion. Reciprocity is especially important in social dilemmas where private interests conflict with Louis vuitton uk interests Rabin 1993 . panel data enables us to control for individual heterogeneity. L. 2007b. Studies show that extrinsic incentives play an important role in decentralized environments Raghu 2003. and M. Incentives A number of experimental studies find that incentives could increase private contribution to public goods Falkinger et al. R. R. This is because the Internet has enabled increasing number of transactions among anonymous partners in electronic marketplaces. 2003. Rabin. J. Kiesler. A simple mechanism for the efficient provision of public goods: experimental evidence. and A. in an ultimatum game. there are also a substantial number of contributors that consistently provide resources to such networks. Oxford University Press. Ravi. Oppenheimer. 1987. Organization Science 7 2 119?C135. Our analysis also considers other motivati ng factors such as re putation or congestion reduction. followed by a discussion of the empirical analysis and results. In such cases. Nature 444 7120 718-723. Fehr. 2006. On the other hand. network users are Louis Vuitton Outlet UK likely to reciprocat e with music files. This is because rewards and punishments can be potentially rendered in the future based on individual labels which deter individuals from being non-cooperative. the peer-to-peer network provides special title called ??Value Users?? to frequent contributors. Second. 26 The result indicates that individuals increase their contribution in response to long wait time when they have high download needs from the network. 12 Most of the online peer-to-peer networks are free to join and open for participation. The design prevents one-to-one interactions. The game plays multiple rounds and players can observe each other??s level of contribution in the previous round. Interview with Linus Torvalds: What motivates free software developers? First Monday 3 3 .?? The important insight from Kandori 1992 is that the enforcement of social norms is itself a public good and. These motivations include reputation Wasko Louis Vuitton Cheap Faraj 2005 . In particular. Sloof. Slaughter. the value of the reward and punishment mechanism and its influence on others?? behavior s are often not obvious to new users. Moreover. Kiesler. Casadesus-Masanell. but a person who fails to punish is in turn punished .. Individual s who only contribute but never download signal that they do not need in-kind cont ributions from others and. Incentives A number of experimental studies find that incentives could increase private contribution to public goods Falkinger et al.?? The important insight from Kandori 1992 is that the enforcement of social norms is itself a public good and. K. Empirical Methodology and Results We use a pair of fixed effect logistic models to test the i ndirect reciprocity effect.