Systems, methods, and other embodiments associated with extracting knowledge from application data and maintaining an ontology based on the extracted knowledge are described. One example system includes a mapping logic to store mappings between application objects and ontology classes and an information extraction (IE) logic that accesses the mapping logic to identify application data to process based on the mappings. The application data may be stored in application data repositories belonging to an enterprise and may be characterized by the application object. Having identified application data to process, the IE logic may locate data in the application data repositories and selectively manipulate an ontology based on selected application data elements.