We describe a model of fundraising in social groups, where private information about quality of provision is transmitted by social proximity. Individuals engage in voluntary provision of a pure collective good that is consumed by both neighbours and non-neighbours. We show that, unlike in the case of private goods, better informed individuals face positive incentives to incur a
cost to share information with their neighbours. These incentives are stronger, and provision of the pure public good greater, the smaller are individuals’ social
neighbourhoods
