1. A method, comprising: maintaining a list of target users of a communication network and respective speech phrases that are characteristic of the target users; selecting a plurality of candidate communication terminals from among multiple communication terminals in the communication network based on a selection criterion; analyzing speech that is communicated via the candidate communication terminals, so as to identify one or more of the speech phrases in the speech; and correlating one of the candidate communication terminals with a target user who is associated in the list with the identified speech phrases.
1. A method, comprising: maintaining a list of target users of a communication network and respective speech phrases that are characteristic of the target users; selecting a plurality of candidate communication terminals from among multiple communication terminals in the communication network based on a selection criterion; analyzing speech that is communicated via the candidate communication terminals, so as to identify one or more of the speech phrases in the speech; and correlating one of the candidate communication terminals with a target user who is associated in the list with the identified speech phrases. 7. The method according to claim 1 , wherein selecting the candidate communication terminals using the selection criterion comprises receiving from the communication network information relating to voice calls conducted in the network, and choosing the candidate communication terminals based on the received information.