1. A system that mitigates privacy concerns in connection with ad targeting or data collection, comprising: a mobile communication host device, comprising: a communication component that: 1) receives a communication transaction between a mobile communication peer device and the host device, and 2) extracts a first set of shared information from the content of the communication transaction between the host device and the peer device, the first set of shared information associated with the peer device; a mapping component that: (1) accesses a social graph stored locally on the host device, the social graph comprising at least: a) a root node including a host profile associated with the host device or a user thereof, and b) a peer node including a peer profile associated with the peer device or a user thereof, and (2) updates the root node and the peer node by populating the root node and the peer node with the first set of shared information extracted by the host device; an advertising component that receives a set of advertisements, stores the set of advertisements locally on the host device, and that selects or tailors a custom ad from the set based upon the updated social graph; and a presenting component that presents the custom ad on the host device.