The Missing Long Tail of the Semantic Web

Professor Fausto Giunchiglia (University of Trento, founding partner of the DataScientia initiative) recently delivered a keynote addressing a key systemic failure in the Semantic Web: the “Missing Long Tail” of ontology reuse. While healthy ecosystems like scientific data and the World Wide Web thrive on a “long tail” distribution, namely, where a few core elements see massive use and many specialized ones see niche reuse, the Semantic Web shows a statistical anomaly. The empirical data about the Semantic Web reveals that less than 5% of ontologies (the “Big Head”) account for over 90% of all reuse, while the remaining 95% are not reused.

This keynote, presented at the in DRTC-ISI Conference 2026 at Documentation Research and Training Centre (DRTC), Indian Statistical Institute, Bangalore – a key partner of the DataScientia initiative – highlighted how the current “all-or-nothing” approach to ontology adoption creates several socio-technical barriers towards encouraging ontology and ontology-based data reuse. To fulfill the vision of a globally interconnected web of data, Professor Giunchiglia proposed a paradigm shift toward reuse via compositionality. By using fine-grained, purpose-driven ontology components rather than monolithic ontology models, the ecosystem can finally support the specialized needs essential for robust, trustworthy data-centric inclusive AI.

Useful links

• Slides available here