A request to present digital content at a client machine associated with a designated network identifier may be received. For each of a plurality of preference characteristics, a respective characteristic query message may be transmitted via a network to a respective plurality of identity nodes via a gossip communication protocol defining a peer-to-peer procedure for transmitting information among the plurality of identity nodes. For each of the plurality of preference characteristics, a respective preference identification response message that includes a respective preference value corresponding with the respective preference characteristic may be received. The designated network identifier may be stored in a trust ledger shared among the plurality of identity nodes. A digital content item may be selected based at least in part on the preference values.