This paper describes a usage-based pricing scheme for distributing digital content over peer-to-peer networks that rewards peer users who actively participate in the distribution process. We present a dynamic distribution model that is used to compare centralized, client-server distribuition with peer-to-peer network distribution. The conventional problem of free-riding in peer-to-peer networks is eliminated or vastly reduced. The participation incentive creates effective peer-to-peer network communities and leads to faster content distribution than in equivalent client-server settings while retaining the same profit level.