1. A method for retrieving person records for applications such as matchmaking or human resource management, wherein retrieval is performed through visual queries on dynamic taxonomies, said dynamic taxonomies being a hierarchical organization of concepts, said concepts also comprising features such as age of person and location of person, said person records being able to be classified under different concepts, said person records and their classification being called an extension, said method comprising: displaying a taxonomy for said retrieval; selecting a subset of interest of said taxonomy in order to refine said retrieval, said subset of interest being specified by selecting taxonomy concepts and combining said taxonomy concepts through boolean operations, or being specified through querying methods, said querying methods retrieving classified person records according to different selection criteria; displaying a reduced taxonomy for said selected subset of interest, said reduced taxonomy being derived from said taxonomy by eliminating from the extension of said taxonomy all person records not in said selected subset of interest and pruning concepts under which no person record in said selected subset of interest is classified; and iteratively repeating said steps of selecting a subset and of displaying a reduced taxonomy to further refine said retrieval, wherein: said hierarchical organization of concepts comprises a set of features, each of said features being a descendant concept of the root concept of said organization, each of said features having as descendants in the taxonomy a set of concepts, each concept in said set of concepts representing either a single value or a set of values for said feature; said person records are classified, for each said feature, under zero or more concepts representing either a single value or a set of values for that feature; said step of displaying a reduced taxonomy either reports only the concepts belonging to the reduced taxonomy or, for each such concept also reports how many person records in the interest set are classified under the concept; and said step of pruning of concepts includes eliminating from the taxonomy the concepts under which no person record in the selected subset of interest is classified, or preventing such concepts from being selected in order to specify interest sets.