An expertise locator enables user defined correspondences between experts and respective certain objects. Each object inherits from classes in a hierarchy. Using the correspondences, a locator processor routine finds a candidate expert about a particular subject area. The candidate expert may be in a correspondence with a certain object whose class is a subclass of the particular subject area. Output may display an indication of the candidate expert, relevant expertise per candidate and/or a list of experts per certain object. In the case of the certain objects being topics, the hierarchy is an ontology of the topics.