1. A computer-implemented method of collecting and managing user profile data in a data communications network, comprising the steps of: storing profile data about users of the network in a network hub; storing, in the data communications network, persona agents associated with the users, wherein the persona agents are interconnected by the hub; wherein each persona agent is operable to perform the following tasks: to collect observational data from an application used by a user, to receive a query from the application, and to deliver a profile segment associated with the user to the application; wherein the contents of the profile segment is determined by a context data portion of the profile data; and wherein the persona agent is further operable to communicate with the hub to obtain the profile segment.