Constitutes the refereed proceedings of the 3rd European Semantic Web Conference, ESWC 2006. This book presents 48 revised full papers with abstracts of 3 invited talks. It organises papers in topical sections on ontology alignment, engineering, evaluation, evolution and learning, rules and reasoning, and searching and querying.

Invited Talks.- Where Does It Break? or: Why the Semantic Web Is Not Just “Research as Usual”.- Toward Large-Scale Shallow Semantics for Higher-Quality NLP.- Usability and the Semantic Web.- Ontology Alignment.- Matching Hierarchical Classifications with Attributes.- An Iterative Algorithm for Ontology Mapping Capable of Using Training Data.- Community-Driven Ontology Matching.- Reconciling Concepts and Relations in Heterogeneous Ontologies.- Empirical Merging of Ontologies — A Proposal of Universal Uncertainty Representation Framework.- Ontology Engineering.- Encoding Classifications into Lightweight Ontologies.- A Method to Convert Thesauri to SKOS.- Ontology Engineering Revisited: An Iterative Case Study.- Ontology Evaluation.- Towards a Complete OWL Ontology Benchmark.- Modelling Ontology Evaluation and Validation.- Benchmark Suites for Improving the RDF(S) Importers and Exporters of Ontology Development Tools.- Ontology Evolution.- Repairing Unsatisfiable Concepts in OWL Ontologies.- Winnowing Ontologies Based on Application Use.- Resolving Inconsistencies in Evolving Ontologies.- Ontology Learning.- Automatic Extraction of Hierarchical Relations from Text.- An Infrastructure for Acquiring High Quality Semantic Metadata.- Extracting Instances of Relations from Web Documents Using Redundancy.- Rules and Reasoning.- Toward Multi-viewpoint Reasoning with OWL Ontologies.- Effective Integration of Declarative Rules with External Evaluations for Semantic-Web Reasoning.- Variable-Strength Conditional Preferences for Ranking Objects in Ontologies.- A Metamodel and UML Profile for Rule-Extended OWL DL Ontologies.- Visual Ontology Cleaning: Cognitive Principles and Applicability.- Rules with Contextually Scoped Negation.- Searching and Querying.- Beagle?+?+?:Semantically Enhanced Searching and Ranking on the Desktop.- RDFBroker: A Signature-Based High-Performance RDF Store.- Towards Distributed Information Retrieval in the Semantic Web: Query Reformulation Using the oMAP Framework.- PowerAqua: Fishing the Semantic Web.- Information Retrieval in Folksonomies: Search and Ranking.- Semantic Annotation.- DEMO – Design Environment for Metadata Ontologies.- An Environment for Semi-automatic Annotation of Ontological Knowledge with Linguistic Content.- Turning the Mouse into a Semantic Device: The seMouse Experience.- Managing Information Quality in e-Science Using Semantic Web Technology.- Annotated RDF.- A Multilingual/Multimedia Lexicon Model for Ontologies.- Semantic Web Mining and Personalisation.- Semantic Network Analysis of Ontologies.- Content Aggregation on Knowledge Bases Using Graph Clustering.- Dynamic Assembly of Personalized Learning Content on the Semantic Web.- Interactive Ontology-Based User Knowledge Acquisition: A Case Study.- Semantic Web Services.- Matching Semantic Service Descriptions with Local Closed-World Reasoning.- The Web Service Modeling Language WSML: An Overview.- On the Semantics of Functional Descriptions of Web Services.- A Minimalist Approach to Semantic Annotations for Web Processes Compositions.- Protocol Mediation for Adaptation in Semantic Web Services.- Semantic Wiki and Blogging.- Ideas and Improvements for Semantic Wikis.- WikiFactory: An Ontology-Based Application for Creating Domain-Oriented Wikis.- Using Semantics to Enhance the Blogging Experience.- Trust and Policies.- WSTO: A Classification-Based Ontology for Managing Trust in Semantic Web Services.- Semantic Web Policies – A Discussion of Requirements and Research Issues.