Mapping online contact information into a contacts list

A presence management system may communicate contact information with mapped values. Contact information may be stored in a hierarchical, extensible structure ("hierarchical extensible contact structure"). Devices in a presence management system utilize a mapping scheme to map contact values (e.g., e-mail address, phone number, etc.) to the appropriate field of the hierarchical extensible contact structure. When devices in the presence management system communicate information for thousands of contacts, employing mapped values to navigate the hierarchical extensible contact structure reduces the size of the messages, thus reducing resource consumption (e.g., bandwidth), particularly on the scale of an enterprise.