A three-dimensional taxonomy server is operative to identify the location of a client device based on three-dimensional positional information received from the client device. The three-dimensional positional information may include global positioning system coordinates, an Internet Protocol address, cellular network information, or any other type of three-dimensional positional information. The three-dimensional taxonomy server may operate in conjunction with another server, such as an advertising server or business search server, to deliver contextual content based on the location of the client device. The contextual content may include a targeted advertisement, a targeted search result, or other type of contextual content.