Abstract: Application service providers (ASP1, ASP2 . . . ) are linked to a mobile telecommunications network (N), such as a cellular telecommunications network, for providing services such as information-providing services to users (MS1, MS2, MS3 . . . ) in the network. For example, one service provider (ASP1) may, on request from a user, provide the address of or directions to the user's nearest pizza outlet. The user's request is intercepted by the network which generates a “user tag” identifying the user, the service provider to whom the request is directed, and the time and date of the request. The network stores the information in the user tag, encodes it and transmits it to the service provider in a form from which the service provider is unable to access the user or obtain the user's identity. The service provider then requests the current location of the user from the network using the user tag to identify the user to the network.