To answer Karen's most recent post, Google can use any WC metadata field. And it's important to note as well that our agreement with Google is not exclusive. We're happy to work with others in the same way. The goal, as I said in my original post, is to support the efforts of our members to bring their collections online, make them discoverable, and drive traffic to library services.
As we have seen from recent postings about the metadata being presented in the Google Books Search service, there are some problems. Although Google claims to have taken the metadata from its library partners, we can look at records in GBS and the record for that item in the library partner database and see how very different they are. It is clear that Google has not retained all of the fields that libraries have provided, and has made some very odd choices about what to keep. Perhaps what we need to do, to help Google improve the metadata, is to make clear what data elements we anticipate we will need in order to integrate the Google product with library services.
When you ask people what metadata is needed for a service, they will often reply something like "everything" or "more is better." I'm going to take a different approach here because I think it is a good idea to connect metadata needs with actual functionality. This not only justifies the metadata, but the functionality helps explain the nature of the metadata that is required. For example, if we say that we want "date of publication" in our metadata, it may seem that we could use the date from the publication statement, which can have dates like "c1956" or "." If, instead, we indicate that we want to use dates in computational research, then it is clear (hopefully) that we need the fixed field date (from the 008 field in the MARC record).
So here are the functions that come to my mind, and I welcome additions. (Do remember that at this point we are only talking about books, so many fields relating to other formats will not be included.) I'll add the related MARC fields as I get a chance.
Need: A thorough description of the edition in question. This will include authors, titles, physical description, and series information.
Need: To be able to combine searches with the same data elements in library catalogs. Generally this means "headings," from the bibliographic record (authors, titles, subject headings).
Function: Collection development
Need: To use GBS to fill in gaps (or make comparisons) in a library's holdings, usually using classification numbers.
Function: Linking to other bibliographic collections or databases
Need: Identifiers and headings that may be found in other collections that would allow linking.
Need: Data elements that can mark a text in time and space (date and place of publication), as well as those that can help segment the file, like language. This function also may need to rely on combining editions into groupings of Works, since this research may need to distinguish Works from Manifestations. Computation will most likely use metadata as a controlled vocabulary, and the full text of the work as the "meat" of the research.