A system and method for provisioning presence application services using a customizable presence data model. An ontology depository having at least one domain-specific ontology model for a particular presence application is provided on a communications network. Presence client software associated with a general-purpose presence entity is customized by referencing a domain-specific ontology model of the ontology depository, whereby the presence entity becomes operable to engage in a particular presence application relating to the domain-specific ontology model.