We have identified a set of indicators to track usage patterns of ontologies developed using the semantically explicit S3DB model (www.s3db.org, Nature Biotechnology (2006) 24(9):1070-1071). These indicators are quantitative measures that assess the maturity of the data model. As a case study, we have allowed experimental researchers working on molecular epidemiology to incubate a data model for molecular epidemiology by restructuring the underlying ontology and evaluating it with real data.