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metadata, resources, and angels & pins

From: Larry Masinter <masinter@adobe.com>
Date: Mon, 22 Jun 2009 06:01:12 -0700
To: Xiaoshu Wang <wangxiao@musc.edu>
CC: www-tag <www-tag@w3.org>
Message-ID: <8B62A039C620904E92F1233570534C9B0118CDAC71D9@nambx04.corp.adobe.com>
My tongue-in-cheek reference to "angels dancing on the head of a pin" confused a few and likely annoyed many; I'm sorry for not indicating humor or a reference, e.g.,  
http://en.wikipedia.org/wiki/How_many_angels_can_stand_on_the_head_of_a_pin%3F 

>    The most  fundamental concepts of the Web are URI, Resource, Representation.  
> Hence, none of these -- meta-URI, meta-Resource, or meta-Representation 
> -- makes any sense.  

I don't think we use those terms, so I suppose the fact that they aren't defined isn't too harmful. And I'm not sure those are the "most" salient concepts needed to discuss metadata meaningfully.

I think I have a concept of "metadata" that is worth developing but I need to work on the articulation of it, but here's a shot:

I think of "metadata" as assertions about a resource; resources are, of course, usually identified by a URI, although in some cases you have a representation "in hand" as well as the metadata about it.
Assertions are not "facts" but rather "opinions" (an assertion by an agent of the agent's belief of facts.)

For metadata access, one agent, with a resource identified by a URI or with a representation in hand, needs to discover (an)other agent(s) and to access the metadata (the other agent's opinions about the resource/representation.)

In this model, "trust" by one agent of another is the measure the association of belief: my browser trusts your server to the extent that the browser believes assertions made by your server. And access to metadata on the web then is a matter of finding a trustworthy source of metadata for resources, and establishing conventions where trust can be delegated, e.g., a "link" header is an assertion by a HTTP server that another agent is a reliable authority of metadata for the resources provided by the first.

This is still a little sloppy, but I hope it gives an indication of the direction I'd like to go in metadata access discussions, and the hope that it will be rewarding and not worthy of Xiaoshu's pessimism.

Larry
--
http://larry.masinter.net

Received on Monday, 22 June 2009 13:02:00 GMT

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