[TagCommons-WG] mechanisms for sharing tag data

[Tom Gruber]

Having identified what might be possible, we can move to looking at how to
accomplish it -- the mechanisms for sharing. 

 

Here is a quick list of ways that people have shared data on the web:

-          point-to-point translation of static data files with a
proprietary data formats

-          point-to-point integration using data derived by crawling and
screen-scraping sites 

-          point-to-point integration using an API (REST, Web Service, etc)
that assumes a particular data model and encapsulates the format in code

-          point-to-point integration accessing databases with documented
schemas

-          common content formats, such as microformats and I-tags

-          common database schemas using a standard schema definition
language

-          common ontologies and RDF for interchange

 

Notice that there are two kinds of sharing -- point-to-point and through a
common mechanism.  You can still write point-to-point mappings using a
common mechanism, but the difference is the common mechanism is N-to-1 to a
canonical format/model, where the others mechanisms require many-to-many
mappings.   For example, to map from one system's API to another, you have
to know the contract and assumptions of each system at operational, format,
and semantic levels.  

 

Within the common convention approaches, the formats are more constrained
than the database schemas, which are more constrained than the ontologies.
In other words, the level of abstraction is going up from formats to schemas
to ontologies, and therefore the differences in contract and assumptions are
going down.  Still, one could provide mechanisms at the format level to
account for semantic distinctions, and enforce them with a social contract.
For instance, microformats encode "semantic" (nonpresentational) information
in the HTML "class" element, such as <div class="vcard">, where the string
"vcard" is known by convention to mean that the markup in the div element is
a format-level representation of a contact.

 

Within the world of databases, there are all kinds of ways to specify
conceptual constraints, and tools for enforcing them.  Ontologies, of
course, are all about specifying conceptual constraints, and the Semantic
Web has machinery for communicating and computing over them.

 

ACTION REQUESTED: 

This message summarizes some mechanisms for sharing, but I would like to ask
members of the group to please pipe in with how you envision the
interoperability could work if we proposed adapting and/or extending some
formal mechanisms and coming to some kind of agreement on it.  For example,
application and tool developers, what practically would you need from the
agreement to enable your work?  Content and research people, what would help
you get the data you need?  Ontology / Semantic Web people, what else needs
to happen to hook up the various levels to make a tagcommons work?

 

For example, here are some teaser topics for this thread:

-          How can a web service translate among or aggregate different tag
data sources?  How can we enable "semantic mashups"?

-          How would a tag ontology map to microformats and what could be
the consequence (we've already heard some about this from Harry Halpin; we
could use a more detailed proposal).

-          How can semantic web ontologies be integrated and/or mapped to
each other?

-          How can ontologies be layered on top of existing tag data sources
that we don't own (for example, how does Annotea talk to del.icio.us?

-          How can database schemas and data sources exposed at that level
be mapped to operational APIs, formats, and ontologies?

 

To ground the discussion, see if you can tie the analysis to one or more of
the use cases we generated, or propose a new use case where needed.

 

Thanks.  It would be great if we could do this phase in a week or so.

 

Best,

Tom

 

 

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