Summary: N3 Wiki
> There's a cool experimental [http://internetalchemy.org/2002/12/n3Wiki N3 Wiki] out there, too.
The primary goal of RdfInWikis is using the ResourceDescriptionFramework to frame a Wiki's meta-data. While the engine may only use and present a fixed set of meta-data (say, the DublinCore), adding more should be a matter of altering the front-end, not altering the internal storage.
This has nothing to do with RDF/XML (though you could use RDF/XML internally). At its heart, RDF contains just two ideas: every predicate is just a URI; every statement (piece of meta-data) is just a resource, like everything else. If a Wiki can handle that, it can handle the following parts of RdfInWikis.
Initially, meta-data comes from two sources: the Wiki engine, and the Wiki user. The former can add a lot of value to a Wiki if combined with some later goals, like ontologies and emission. Many Wikis provide an RSS feed in addition to RecentChanges-style pages, allowing remote aggregation of updates to many Wikis. DublinCoreForWiki suggests a full set of DublinCore meta-data that can be emitted for existing Wiki pages.
How to manually add RDF meta-data to a page is the focus of some current research. Perhaps the most Wiki-like approach is to extract information from the plain text of the page, using a prescribed MetadataSyntax. Again, the goal should be to pick a method that extends simply and logically to cover a wider range of meta-data.
This has no connection with RDF/XML, and probably shouldn't, as RDF/XML is not generally regarded as human-readable.
See also MeatBall:RdfForWikis.
Once your Wiki starts supporting larger sets of properties, you will want a standardised way of writing an ontology, teaching the Wiki to understand and build upon the meta-data it's given. This gives us, for instance, indices.
This has nothing to do with RDF/XML. OWL (WebOntologyLanguage) is appropriate here. Eventually, there will be choices about what to store and what to re-deduce if an ontology uses the more complex parts of OWL, since the quantity of implied meta-data begins to dwarf what is actually provided.
Meta-data, like everything, has issues of scaling. Small quantities can be used for indices and the like, but when a category like biology has hundreds of sub-categories and thousands of entries, other approaches will be needed. Simple query forms will help meta-data presentation scale, and graphical displays can be provided for that high-tech twist.
More complex querying systems can only be designed once a site has accumulated lots of meta-data. Visions of intelligent agents and natural-language query systems are nice, but cannot be made concrete until earlier parts of RdfInWikis have been adopted on a wide scale.
RDF/XML is a standardised way of emitting meta-data for other machines to read, and any Wiki using RDF internally will probably want to provide a RDF/XML stream. This does not prohibit emitting DC in <meta> elements or in human-readable form; indeed, the more ways you can skin a cat, the better. (All this repetition must be done by the Wiki, though, not by people.)
Other candidates for the emission format are RSS 1.0 (a deviant of RDF/XML) and TriX?.
Reading in standardised meta-data allows one to connect sites (UnifiedCommons).
This is probably the hardest step. Reading arbitrary RDF/XML is tough, as the standard contains a lot of special cases for people who wanted to write by hand. Other formats might prove more tractable, but one must still handle external meta-data that changes, and may even have cyclic dependencies on one's own meta-data emissions.
There are also issues of balancing automation with defence against spam. If we make it easy for one site to hand us meta-data, we make it easy for spammers to overwhelm us. WebLogs are continually encountering this problem as the major 'blogs get targeted by advertisers. This ties in with existing Wiki technology like StableCopy.
There are several possible overlaps between the ResourceDescriptionFramework and Wiki techniques/technology.
Right now a text search for the above phrase doesn't find the results indicated. The page [NeuroWiki:HippocampalBasketCell?] says "Also known as perisomatic inhibitory cells" and also "These interneurons are necessary for the HippocampalThetaRhythm?", and the hippocampalThetaRhythm is a type of oscillation (in fact, the page is even in NeuroWiki's categoryOscillation). A human who read both pages would know that, but the computer doesn't.
(Maybe enough links? )
I realize that Dublin Core is not the be-all and end-all of RDF, but the stuff on DublinCoreForWiki is RDF, and it is for wikis. The simple Dublin Core stuff is valid XML, but it's also valid RDF. The new extended Dublin Core recommendation is RDF-only. The extended version, at the bottom of the page, has much of the functionality (links, versions, etc.) requested on MeatBall:RdfForWikis.
Sorry, I still don't see why DublinCoreForWiki shouldn't be linked from this page. So I put the link back in.
If you have a very specific purpose for this page, you need to add it up at the top, here. Otherwise, I see "RDF in Wikis" meaning exactly that: using RDF in wikis. The mechanism described in DublinCoreForWiki is an example of that.
OK, I'm having a lightbulb moment. Chris, are you trying to describe building RDF descriptions with a Wiki technique? Or using RDF to describe (traditional) Wiki resources like pages and possibly images or other files? Or a combination of both -- using wiki technique to create RDF that describes other wiki-created resources?
Oh, hey: I guess I'll just ask that question in DocumentMode.
But I'll go ahead and copy it anyway if no one objects.