1. A method of using a computer to determine a reputation of an object in a reputation system, comprising: receiving reports from clients in the reputation system, the reports identifying an object detected at the clients; determining information about the clients from the reports; generating confidence metrics for the clients responsive to the determined information about the clients, the confidence metrics indicating amounts of confidence in the veracity of the reports received from the clients; calculating a reputation score of the object responsive at least in part to the reports from the clients and the confidence metrics for the clients; and storing the reputation score of the object.