Semantic wiki 1
Semantic wiki
A semantic wiki is a wiki that has an underlying model of the knowledge described in its pages. Regular, or
syntactic, wikis have structured text and untyped hyperlinks. Semantic wikis, on the other hand, provide the ability to
capture or identify information about the data within pages, and the relationships between pages, in ways that can be
queried or exported like a database.[1] [2]
Semantic wikis were first proposed in the early 2000s, and began to be implemented seriously around 2005. As of
2011, the best-known semantic wiki software may be Semantic MediaWiki, while the best-known standalone
semantic wiki may be Freebase.
Key characteristics
Formal notation
The knowledge model found in a semantic wiki is typically available in a formal language, so that machines can
process it into an entity-relationship or relational database.
The formal notation may be included in the pages themselves by users, as in Semantic MediaWiki; or it may be
derived from the pages or the page names or the means of linking. For instance, using a specific alternative page
name might indicate a specific type of link was intended. This is especially common in wikis devoted to code
projects. It should be easy to examine and fix, e.g. to identify problems in parsing and conventions introduced by
newer users.
In either case, providing information through a formal notation allows machines to calculate new facts (e.g. relations
between pages) from the facts represented in the knowledge model.
Semantic Web compatibility
The technologies developed by the Semantic Web community provide one basis for formal reasoning about the
knowledge model that is developed by importing this data. However, there are also a wide array of technologies that
work on ERD or relational data.
Example
Imagine a semantic wiki devoted to food. The page for an apple would contain, in addition to standard text
information, some machine-readable or at least machine-intuitable semantic data. The most basic kind of data would
be that an apple is a kind of fruit - what's known as an inheritance relationship. The wiki would thus be able to
automatically generate a list of fruits, simply by listing all pages that are tagged as being of type "fruit." Further
semantic tags in the "apple" page could indicate other data about apples, including their possible colors and sizes,
nutritional information and serving suggestions, and so on. These tags could be derived from the text but with some
chance of error - accordingly they should be presented alongside that data to be easily corrected.
If the wiki exports all this data in RDF or a similar format, it can then be queried in a similar way to a database - so
that an external user or site could, for instance, request a list of all fruits that are red and can be baked in a pie.

Semantic wiki 2
Use in knowledge management
Where wikis replace older CMS or knowledge management tools, semantic wikis try to serve similar functions: to
allow users to make their internal knowledge more explicit and more formal, so that the information in a wiki can be
searched in better ways than just with keywords, offering queries similar to structural databases.
Some systems are aimed at personal knowledge management, some more at knowledge management for
communities. The amount of formalisation and the way the semantic information is made explicit vary. Existing
systems range from primarily content-oriented (like Semantic MediaWiki) where semantics are entered by creating
annotated hyperlinks, via approaches mixing content and semantics in plain text, via content-oriented with a strong
formal background (like KiWi), to systems where the formal knowledge is the primary interest (like Metaweb),
where semantics are entered into explicit fields for that purpose.
Also, semantic wiki systems differ in the level of ontology support they offer. While most systems can export their
data as RDF, some even support various levels of ontology reasoning.
History
In the 1980s, before the Web began, there were several technologies to process typed links between collectively
maintained hypertext pages, such as NoteCards, KMS and gIBIS. Extensive research was published on these tools by
the collaboration software, computer-mediated communication, hypertext, and computer supported cooperative work
communities.
The first known usage of the term "Semantic Wiki" was a Usenet posting by Andy Dingley in January 2001.[3] Its
first known appearance in a technical paper was in a 2003 paper by Austrian researcher Leo Sauermann.[4]
Many of the existing semantic wiki applications were started in the mid-2000s, including Semantic MediaWiki
(2005), Freebase (2005) and OntoWiki (2006).
June 2006 saw the first meeting dedicated to semantic wikis, "SemWiki2006", co-located with the European
Semantic Web Conference in Montenegro.[5]
The site DBpedia, launched in 2007, though not a semantic wiki, publishes structured data from Wikipedia in RDF
form, which enables semantic querying of Wikipedia's data.
In March 2008, Wikia, the world's largest wiki farm, made the use of Semantic MediaWiki available for all their
wikis, thus allowing all the wikis they hosted to function as semantic wikis.[6]
In July 2010, Google purchased Metaweb, the company behind Freebase.[7]
Semantic wiki software
Category: Semantic wiki software
• ArtificialMemory [8] - Personal Semantic Wiki and Argumentation System
• Freebase – web database with semantic-wiki-like properties
• KiWi
• OntoWiki
• PhpWiki
• Semantic MediaWiki - an extension to MediaWiki that turns it into a semantic wiki
• SMW+ - an application that incorporates Semantic MediaWiki as well as other extensions
• Tiki Wiki CMS Groupware - includes a semantic links feature[9]
• Wagn - Ruby on Rails-based
• zAgile Wikidsmart [10] - semantically enables Confluence