This article aims to examine the impact of group size on the provision of collective good

provided by P2P file-sharing communities. Olson (1965) argued that small communities are

more able to provide collective actions. Using an original database on Bittorrent file-sharing

communities, our article finds a positive relation between the size of a community and the

amount of collective good provided. However, the individual propensity to cooperate

decreases with group size. These two features seem to indicate that P2P file-sharing

communities provide a pure (non rival) public good. We also show that specialized

communities are more efficient than general communities to encourage cooperative behavior.

Finally, the rules designed by the managers of a community play an active role to stimulate

voluntary contributions and improve the self-sustainability of file-sharing.Lire l’article complet