Silvio Peroni has recently created LODE (Live OWL Documentation Environment; http://lode.sourceforge.net/), a new ontology visualization service that automatically extracts classes, object properties, data properties, named individuals, annotation properties, general axioms and namespace declarations from an OWL or OWL2 ontology, and renders them as ordered lists, together with their textual definitions, in a human-readable HTML page designed for browsing and navigation by means of embedded links. The Cascading Style Sheets used for LODE are based on the W3C CSSs for Recommendation documents.
This LODE service is an open source development, and can be freely used, as described at http://lode.sourceforge.net/. It may be used in conjunction with content negotiation to display the human-readable LODE version of an OWL ontology when the user accesses the ontology using a web browser, or alternatively to deliver the OWL ontology itself when the user accesses the ontology using an ontology editing tool such as Protégé and NeOn Toolkit. It is in this way that LODE is being employed to visualize the SPAR (Semantic Publishing and Referencing) Ontologies (http://purl.org/spar/).