standard language like RDF or OWL, or some database directly populated by the tool that withdraws the semantics from the raw data. Separate versioning support or correction editing for the formalized content may also be provided. Provenance support for the formalized content, that is, tagging the author of the data separately from the data itself, varies. What data can get formalized also varies. One may be able to specify types for pages, categories, or paragraphs or sentences (the latter features were more common in pre-web systems). Links are usually also typed. The source, property, and target may be determined by some defaults, e.g. in Semantic MediaWiki the source is always the current page. Reflexivity also varies. More reflexive user interfaces provide strong ontology support from within the wiki, and allow it to be loaded, saved, created, and changed. Some wikis inherit their ontology entirely from a pre-existing strong ontology like Cyc or SKOS, while, on the other extreme, in other semantic wikis the entire ontology is generated by users. Conventional, non-semantic wikis typically still have ways for users to express data and metadata, typically by tagging, categorizing, and using namespaces. In semantic wikis, these features still typically exist, but integrated these with other semantic declarations, and sometimes with their use restricted. Some semantic wikis provide reasoning support, using a variety of engines. Such reasoning may require that all instance data comply with the ontologies. Most semantic wikis have simple querying support (such as searching for all triples with a certain subject, predicate, object), but the degree of advanced query support varies; some semantic wikis provide querying in standard languages like SPARQL, while others instead provide a custom language. User interface support to construct these also varies. Visualization of the links especially may be supported. Many semantic wikis can display the relationships between pages, or other data such as dates, geographical coordinates, and number values, in various formats, such as graphs, tables, charts, calendars, and maps. See also Microformats Ontology RDF, RDFS, OWL, SPARQL Business Intelligence 2.0 (BI 2.0) Software and websites: Freebase Gardenology.org Math Images Project Metavid NeuroLex OpenEI SKYbrary SNPedia Wikidata References External links Semantic wiki article at SemanticWeb.org Semantic wiki projects - contains a list of active, defunct and proposed semantic wiki applications SemanticWiki mini-series - a mini-series of online conferences about semantic wikis that ran in 2008 and 2009. Semantic wiki software Wikis by genre