When teaching on the role and importance of structured and standardized data, BioPortal is an indispensible reference. It demonstrates the sheer size and number of ontologies, and the cross-ontology search helps to appreciate gaps, overlaps and target areas of and between ontologies. The annotator, mappings, and SPARQL endpoint help to provide insight in the potentials and challenges of building and using the linked open data cloud in the domain of healthcare and life sciences.