Patent ID: 8626933

Claim:
A method of providing a service to a plurality of users of communication devices present in a geographic service area covered by the service, the method comprising: associating each specific one of the communication devices with a specific one of the plurality of users; conditionally alerting a particular one of the plurality of users, via a communication device associated with the particular user, to a presence of another communication device of another one of the plurality of users in the service area, wherein the conditional alerting takes place upon a determination comprising: that the other user is registered as a buddy of the particular user, that at least one of the particular communication device and the other communication device is a mobile communication device, and that a geographical distance between the particular communication device and the other communication device is less than a first predetermined threshold; and running a succession of polling cycles, wherein in each specific one of the polling cycles, mobile ones among the communication devices are sequentially polled with regard to geographic location and according to a specific ranking determined in a preceding one of the polling cycles, wherein the specific ranking is determined to minimize a value of a sum of terms, and wherein each respective one of the terms is indicative of a respective difference between a possible rank of the respective mobile communication device of the respective user and a respective possible other rank of the respective other mobile communication device of the respective other user registered as the buddy of the respective user.