Metadata is cataloging done by men.The point of the joke (yes, I know it isn't funny if you have to explain a joke) is that the term metadata was coined to make cataloging palatable to the computer community, and that they're really the same thing. We often use the terms interchangeably, but my recent forays into the world of RDA development have led me to look more closely at the meaning of the term cataloging, and I have concluded that metadata creation and cataloging are very different activities. I do consider a catalog record to be a form of metadata, but not all metadata, and not even all bibliographic metadata, is cataloging.
It's not just a matter of having rules or not having rules, however. Although it seems obvious to say this, the goal of cataloging is the creation of a catalog. Catalogers create entries for the catalog using rules that are designed to produce not only a certain coherent body of data, but to enforce a particular set of functions (access via alphabetically displayed headings is an example of a function) that are required to support the catalog. The catalog entries create the catalog.
Library cataloging, as a form of metadata, has traditionally had well-defined goals. The catalog records were defined in terms of the catalog's physical structure and functions. With the card-based cataloging rules, from the ALA rules through AACR2, each catalog entry was a precise, unchangeable unit of the catalog, a cell in a well-designed body. As the cataloger created the record, she could know exactly how headings would be used, exactly where they would be filed in the catalog, exactly what actions users would have to take to navigate to them.
This precision ended with the creation of the online catalog. Catalog entries that had been created for a linear card file were being accessed through keyword searches; displays no longer followed the "main entry" concept; the purposeful unit created by the cards in the catalog was destroyed. There was no longer a match between the catalog and the cataloging.
Which is why many of us are having a hard time with the development of our future cataloging rules, RDA. RDA doesn't define the catalog that it is creating catalog entries for, which brings into question how decisions are being made. What is the concept of a catalog in this highly mutable world of ours? I can't imagine that we can create cataloging rules until we define the catalog (or catalogs) that the rules pertain to. It may not be the highly structured system that we had with the card catalog, where access points were THE access points and every card had its one place in the ordered universe that was the catalog. Still, we need to define the catalog before we can expect to create the entries that go into it. We can start with the FRBR "find, identify, select, obtain," but we must close the enormous gap between those functions and actual catalog entries.