I'm being quite wooly here, but I think we may be able to avoid the kind of issues Lars seems to be worried (of remote, centrallised, irrelevant meta data) about by wikifing the semantics themselves, making them fluid and negotiable like the rest of the wiki. For example, I could write:

King Harold died in [[meta:DiedIn:1066]] during the [[Battle of Hastings]] in [[that year|meta:Battle:1066]]. 

Now, neither DiedIn or Battle need be defined beforehand.  These could themselves be pages that describe further semantic relationships, eg that battles have a start and end time, participants and a location.  These could be added by other participants (possibly prototyped in natural English with links to relevant wiktionary or wikipedia articles) along with references to existing relationships.  And talk pages, of course.

Elsewhere I might write:

Fred Bloggs lived until [[meta:LivedUntil:1977]].

This could be dealt with as a synonym for DiedIn in a way similar to page redirects.  I'm concious that there are other examples where ways of stating relationships are incompatible, though I can't think of any at the moment. Consequently I can't concieve of how they might work yet.

There are relationships that are complementary, eg the ball is in the box if and only if the box contains the ball. How that and similar types of relationships can be 'understood' by the system to be equivalent without vast amounts of processing, I must admit I have no idea.  Some of you seem to have studied this topic.  Any thoughts? 

Storing relationships and their semantics allow us to do things like automatically create timelines of battles and other categories of historical events.  Webs of relationships between objects (and meanings of words) would start to be set up allowing other classification and possibly even reasoning of sorts to be performed.  Whether these could be made practical to carry out, particularly as edits occur, I don't know.

There's lots more to be usefully said on this topic (possibly not be me, I don't think I really grasp it yet), but far more that is not useful.  I hope the list will not be clogged by wild extrapolations, but debate around this topic may point to simple, implementable solutions. 

However, is wikitech-L the place for such debate? Should there be a page (or pages) on meta.wiki.org called "applications of metadata" and "semantics in the wiki"?

Russell Jones

Evan Prodromou wrote:
"LA" == Lars Aronsson <lars@aronsson.se> writes:
            

    LA> You have to provide some incentive for the editor of an
    LA> article to input the metadata.  How are you going to succeed
    LA> in attracting wikipedia article editors?

That's a worthwhile question. Here's some possible answers:

* Automatic indices. Use metadata to automatically create indices to
  the encyclopedia, like [[list of X]]. We could probably also do some
  fun automatic stuff with the timeline and date pages.

      [[meta:year=1885,born]]
      [[meta:year=1923,died]]

* Metadata-guided search. Currently we have three levels of search:
  exact title (the "Go" button), title match, and full-text match. I'd
  say that a metadata search (probably placed, in order of value,
  between exact title and title match) would be helpful. We could
  leave it on (like "Go") even when full-text search was too
  compute-intensive.

* Metadata in search results: even for full-text search, it can be
  useful to return metadata. Like, if I search for "Springfield", it'd
  be kind of nice to see:

     - Springfield
       is-a: city, is-part-of: Kentucky
       
       (matching text here)

     - Springfield
       is-a: city, is-part-of: Missouri
       
       (matching text here)

     - Springfield
       is-a: fictional city, genre: animation
       
       (matching text here)

  Yes, the presentation is lame -- I don't think we'd ever show raw
  tags like that. But you get the picture.

* Geographical proximity. Frankly, I think ICBM tags make the whole
  thing worthwhile, just on their own. But that's my own bete noire.

* Breadcrumb navigation. It's fairly cumbersome to write, in
  [[cyclotron]], that "A cyclotron is an [[instrument]] used in
  [[particle physics]] which is a branch of [[physics]] which in turn
  is a [[natural science]] which is a kind of [[science]]." After all,
  the article isn't about natural science -- why describe it from
  here?

  But with metadata we could have a breadcrumb link thing that says:

    sciences > natural sciences > physics > particle physics > instruments 

Frankly, what I think is that we just need to have one or two
applications of the metadata, and people are going to think up
brilliant new ones. They'll send patches for MediaWiki to do it, or
they'll send RFEs, or they'll develop their own bots or whatever.

In other words, I don't think we're going to need to worry about
getting people into doing metadata; we're going to have to worry about
keeping up!

~ESP