Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Customers write book reviews for Amazon.com and rate stores at BizRate.com. Car drivers call up radio stations to report traffic jams or radar traps. In many cases individuals share their information to the benefit of an unknown group of recipients, even though doing so is costly for the provider. In contrast to a standard public good, providers have no immediate benefit from information public goods. The paper reports the results of an experimental study on information sharing under two payoff conditions (opportunity announcement and hazard warning) and two information conditions (anonymous and identified provider). The experimental results show a substantial degree of information sharing. Information on extreme opportunities and extreme hazards is significantly more often provided than information on moderate prospects. Identification only plays a role in case of extreme opportunities and not in case of hazard warnings.