Embodiments of a system and method of tagging network traffic with relevant user demographic and location information for facilitating the delivery of directed media are described. A tag processing module within a router device coupling a client computer to a destination site served by a server computer intercepts a request from a client computer to a server computer over a network. The tag processing module determines a unique device identifier corresponding to the client computer, generates a local user identifier for the client computer by performing a one-way hashing operation on the unique device identifier, derives demographic and location information for a user of the client computer, generates a request identifier associated with the intercepted request by encrypting the local user identifier, demographic information and geographic location information in an alphanumeric string, and embeds the alphanumeric string in an extensible field of a packet within the request to generate a tagged request identifier.