I've had a terrible time trying to understand Open Annotation (why is this not just an RDF graph showing a relationship between things? Why does it get its own formal definition?), and now I'm looking at BIBFRAME annotation, pretty much guaranteeing even greater confusion on my part.

BIBFRAME annotation is described as:

The parties and objects involved in a BIBFRAME Annotation are:

The Target of the Annotation: A BIBFRAME Work, Instance, or Authority. The book, in part 1 of the illustration below.
The Annotation Body, which is the payload of the Annotation. The book review below.
An author, artist, reviewer, etc. who writes the Annotation Body. (This role is not represented formally in the Annotation model, but is mentioned here to clearly distinguish it from the Annotator.) The Reviewer below.
The Annotator, who asserts the Annotation. (The Annotator is not necessarily the same party as the author, etc. who wrote the Annotation.) The Annotator in part 2 of the illustration.
The Annotation itself , which points to the Body, Target, and Annotator. The Annotation, in part 2 of the illustration. [1 - section 2.2]

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From this description I conclude that "Annotation" is a special instance of "node" -- a node with some semantics and a limited set of properties: links to a particular set of things. I'm still totally unclear why this is a special case in RDF, since things and links to things are inherent in the model.

What BIBFRAME seems to be doing is using Annotation to mean "optional information." I conclude this from section 2.1 of the BIBFRAME annotation document [1 - section 2.1]:

What is a BIBFRAME Annotation?

For purposes of this model, a BIBFRAME Work, Instance, or Authority is an abstract resource. Different institutions may have different views of any given BIBFRAME Work, Instance, or Authority. For example, for a given BIBFRAME Work, InstitutionA and InstitutionB may each have a view of the Work, bf:Work A and bf:Work B.

Certain information is integral to a Work - title and author, for example - and might be reasonably expected to be reflected in both views. Other information might be part of one view but not the other - information asserted (possibly by a third party) about the Work, which Institution A chooses to integrate into its view but Institution B chooses not to (or vice versa).

A BIBFRAME Annotation is an assertion, by any party, about a BIBFRAME resource (Work, Instance, or Authority) that any institution holding a view of that resource may choose to integrate into its view, or choose not to.

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There seem to be two things going on here. One is that different users of BIBFRAME will make different choices about what is "integral" to Work, Instance and Authority.

The other thing is that there are *optional* bits of information that can be encoded as Annotations, and these can be ignored by anyone not interested in making use of them. Unfortunately, defining some elements as "unessential" means that others must be defined as "essential."

This means that one person's "integral bit" with be another person's Annotation. Thus having annotations doesn't mean simply that you can ignore all Annotations, nor does it mean that you do not need to make choices among the "integral bits" that come from other sources. In this sense, Annotation doesn't appear to me to solve the problem of differences in cataloging.

I *could* understand (although not necessarily favor) a regime in which there is a defined core (oh, yes, that word again) and everything else is an annotation. That is, everything else is optional. But the definition of Annotation here does not seem to make this separation.

Another possibility for Annotation would be to define it as being "third-party information" -- anything not provided by the cataloger and not provided for in the cataloging rules. I'm not saying this would be a good idea, but it would be a clear separation between Annotation and not-Annotation.

If there isn't some clear separation, then I don't see a great advantage over letting metadata users select elements based on data elements and provenance.

What have I missed?

[1] http://bibframe.org/documentation/annotations

-- 
Karen Coyle
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