Utility and privacy effects of a user action in a communication system

The present invention concerns a method of determining an effect of a user action taken with respect to an item in a communication network. The item is associated with data content in the communication network. The method comprises: (a) determining (31) public information in the communication network (1), the public information comprising ratings given by user actions taken with respect to the items in the set of items; (b) determining (33) a probabilistic user model of a first user, the probabilistic user model being at least partially derived from the public information; (c) determining (35) a first disclosure degree for a second user, the first disclosure degree depending on the probabilistic user model, the first disclosure degree indicating information content amount of a user profile of the second user before an action by the second user taken with respect to an item in the set of items; (d) determining (37) a second disclosure degree for the second user, the second disclosure degree depending on the probabilistic user model, the second disclosure degree indicating information content amount of the user profile of the second user after the action by the second user; and (e) determining (39) a disclosure risk of the action by the second user on the item in the set of items. The disclosure risk depends on the first and second disclosure degrees.