From W3C Wiki
PeriPeri is a prototype SemanticWiki, an attempt to create a more natural approach to the problem than creating vastly complicated edit forms or editing XML.
To start with, meta-data is added to the top of a page like an e-mail header. All the standard DublinCore elements are accepted, with
subject being currently the most commonly-used. An example, taken from the page PeriPeri:DublinCore:
Abstract: A small set of widely applicable meta-data Subject: PeriMechanics Subject: PeriPeriBasics Is-Part-Of: PeriPeri:RdfForWikis Requires: MetadataSyntax
The PeriPeri engine will display this nicely in HTML, but it will also automatically provide an RDF/XML feed for it. (I plan to add TriX support.)
Implications are also provided. The above header will, for example, cause the Dublin'Core page to be listed, along with its
abstract, on the Rdf'For'Wikis page under Has Part'.
Internally, PeriPeri stores all its pages in individual plain-text files. For performance, it caches RDF in a MySQL database, and this is where all implications are stored.
To handle the ever-changing pages of a Wiki, PeriPeri's RDF engine has the (I believe) unique feature of a fully-functional garbage collector, ensuring implications are always correct.