Management of peer-to-peer networks using reputation data

Method of operating a computer entity in a peer-to-peer network are provided in which the computer entity carries out a reputation management process in which it collects reputation data items and uses them to monitor at least one other computer entity of the network. Embodiments of the invention include generating a message in response to changes in at least one said reputation data item, with the addition of a) the reputation data describing at least one user's perception of a performance parameter of one or more of the computer entities or b) a voting arrangement causing a voting protocol to be applied to determine a group action of a plurality of peer computers about which reputation data has been collected. Another embodiment comprises collecting reputation data from at least one other computer entity of a network, the reputation data describing at least one user's perception of a performance parameter of one or more of the computer entities.