1. In a data communications network having a plurality of personal mobile data communications devices operated by respective users and an information service with which the personal mobile data communications devices communicate, a computer-implemented method of processing place-and-people based information at one of said personal mobile data communications devices, the method comprising: transmitting information to identify to the information service a list of people about whom the user of the personal mobile data communications device desires to be informed by the information service, wherein the presence of each identified person on the list indicates previous consent by the respective identified person to share information with the user via the information service, and wherein identifying information for each identified person on the list is accessible by the user prior to receiving any information about the identified people from the information service; transmitting a report of the location of the personal mobile data communications device to the information service; and receiving from the information service information indicating which of the identified people are within a specified proximity of the user.