This paper proposes reputation mechanisms that rely on collaborative ratings and personalized evaluation of the various ratings assigned to each user. Reputation is usually defined as the amount of trust inspired by a particular person

informs ® doi 10.1287/mnsc.1050.0379

Despite the inherent risk arising from separating buyers and sellers, networked online marketplaces are proliferating. We describe how online auction marketplaces take advantage of institutional structures to build buyer trust in auction sellers, mitigate risk, increase satisfaction, and promote transaction intentions. It is hypothesized, based on institutional trust (Zucker 1986), that buyer trust in auction sellers can be increased, beyond past experience with sellers, through structural assurances, such as buyer-driven certification, auction house escrows, and credit card guarantees. We examined buyer transaction intentions, mediated by trusting beliefs, risk reduction, and satisfaction. The model is tested with 274 buyers in Amazon’s online auction marketplace. The results support the hypotheses, highlighting the importance of institution-based trust in online networks. Implications are discussed. Keywords: Institution-based trust, online auctions, institutional structures, certification, escrows, third-party guarantees

As a more diverse population of users moves online, understanding how to help those groups work together and leverage their diverse skills poses a significant challenge for human-computer interaction. This paper presents a case study of the design of an online community that supports kids interviewing elders to build up a shared database of oral history. Two pilot studies with existing technology are presented, and a software design based on those studies is described. In addition, a formative evaluation of the software is discussed, along with future work. This work shows the value of prototyping with existing technology in order to uncover user needs in an online environment. Keywords CSCL, online community, children, user-centered design

We describe an Agent Mediated marketplace, with dynamically changing reputation ratings. In this marketplace, the seller reputations are updated in a collaborative fashion based on the performance of the user in the delegated tasks. We study the market with computer simulations of multiagent interactions, where sellers learn how to price their services dynamically. We first present some simple dynamic pricing methods and we investigate the different equilibria reached, based on the level of intelligence of the selling agents, the level of price-importance elasticity of the buying agents, and the level of unemployment in the marketplace. We then compare the equilibria reached with a theoretically "optimal " equilibrium that we show to exist. Based on the results of this comparison we design a new dynamic pricing algorithm that we experimentally show to be almost optimal for reputation-brokered agent mediated marketplaces.

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Reputation reporting systems have emerged as an important risk management mechanism in online trading communities. However, the predictive value of these systems can be compromised in situations where conspiring buyers intentionally give unfair ratings to sellers or where sellers discriminate on the quality of service they provide to different buyers. This paper proposes a set of mechanisms that eliminate or significantly reduce the negative effects of such fraudulent behavior. The proposedmechanisms can be easily integrated into existing online reputation systems in order to safeguard their reliability in the presence of deceitful buyers and sellers. 1.

Abstract—This paper draws lessons from research on trust in social sciences. Human beings have an innate drive towards cooperation including a basic willingness to trust strangers, and to altruistically punish defectors, even at a high cost to themselves. The ability to trust people, i.e. having an environment, in which people can be generally assumed to be benevolent, is considered important for democracy and working markets. Market efficiency and creation of communities are of importance for the future of communications. Based on the findings, a number of architectural principles that have effects on trust are proposed: prefer code, multi-dimensional compensation, intention neutrality, balancing privacy and attribution, internalising and market shaping, and explicit representation of trust and reputation. The findings indicate that a technical architecture that fosters trust is necessary for the future of communication networks. I.

New York: Russell Sage 2008. Stimulating comments of and discussions with Jeroen Weesie and other members of our Utrecht group “Cooperation in Social and Economic Relations ” are gratefully acknowledged. We also acknowledge helpful comments from participants of the Russell Sage Foundation “Rational Choice Social Research Workshop ” and specifically from our discussant, Simon Gächter. Financial support for Buskens was provided by the Royal Netherlands Academy of Arts and Sciences (KNAW) for the project “Third-Party Effects in Cooperation Problems ” and by Utrecht University for the High Potential-program “Dynamics of Cooperation, Networks, and

Reputation systems have become increasingly popular in virtual communities as a way to record and communicate the reputation information of the members. However, different reputation systems use different presentation formats and their effects on decisions in terms of evaluating positive and negative ratings remain unclear. A controlled experiment is proposed using the preference ladder procedure to elicit subjective preferences in three commonly used presentation formats. One format presents the negative and positive ratings side by side; one presents the information as a percentage of total ratings that are positive; the third presents the difference between the positive and negative ratings, the format used by eBay. Results of the preliminary data analysis suggest that people weigh the positive and negative information to different extents in the three formats. Presenting reputation in the difference format tends to make a person weigh the negative information less, making the person more forgivable. The finding is possibly due to the salience of the negative ratings in the various presentations.