Method for determining an identity associated with a contacting identifier received in a first communication device, comprising the steps of: investigating if there is an entry of the contacting identifier in a contacts register of the first communicating device, and in case there is no such entry: - sending a query to a communication device associated with the contacting identifier, - in case no answer is received from the communication device associated with the contacting identifier, locating, in the contacts register, communication devices (12, 14) in a set of communication devices which includes a contacting identifier lookup server providing a lookup service, and which set further includes at least one personal communication device, - sending, only in case no answer is received from the communication device associated with the contacting identifier, a query regarding the contacting identifier to the server, which in turn broadcasts the query to at least some of the communication devices (12, 14) in the set of communication devices, in order for the communication devices (12, 14) to investigate a contacts register of its own and locate the identity associated with the contacting identifier, and - receiving data regarding the identity associated with the contacting identifier from at least some communication device (12, 14) in the set of communication devices. investigating if there is an entry of the contacting identifier in a contacts register of the first communicating device, and in case there is no such entry: - sending a query to a communication device associated with the contacting identifier, - in case no answer is received from the communication device associated with the contacting identifier, locating, in the contacts register, communication devices (12, 14) in a set of communication devices which includes a contacting identifier lookup server providing a lookup service, and which set further includes at least one personal communication device, - sending, only in case no answer is received from the communication device associated with the contacting identifier, a query regarding the contacting identifier to the server, which in turn broadcasts the query to at least some of the communication devices (12, 14) in the set of communication devices, in order for the communication devices (12, 14) to investigate a contacts register of its own and locate the identity associated with the contacting identifier, and - receiving data regarding the identity associated with the contacting identifier from at least some communication device (12, 14) in the set of communication devices. - sending a query to a communication device associated with the contacting identifier, - in case no answer is received from the communication device associated with the contacting identifier, locating, in the contacts register, communication devices (12, 14) in a set of communication devices which includes a contacting identifier lookup server providing a lookup service, and which set further includes at least one personal communication device, - sending, only in case no answer is received from the communication device associated with the contacting identifier, a query regarding the contacting identifier to the server, which in turn broadcasts the query to at least some of the communication devices (12, 14) in the set of communication devices, in order for the communication devices (12, 14) to investigate a contacts register of its own and locate the identity associated with the contacting identifier, and - receiving data regarding the identity associated with the contacting identifier from at least some communication device (12, 14) in the set of communication devices.