Abstract
Standard economic theory does not capture trust among anonymous Internet traders. But when traders are allowed to have social preferences, uncertainty about a seller’s morals opens t he door for trust, reward, exploitation and reputation building. We report experiments suggesting that sellers’ intrinsic motivations to be trustworthy are not sufficient to sustain trade when not complemented by a feedback system. We demonstrate that it is the interaction of social preferences and cleverly designed reputation mechanisms that solves to a large extent the trust problem on Internet market platforms. However, economic theory and social preference models tend to underestimate the difficulties of promoting trust in anonymous online trading communities.