Welcome to the Metadata Millennium: A Complete Overview of What Metadata Can Do for Publishers
This begs the question of one of the biggest problems in publishing metadata right now: the lack of a widely adopted, standard work identifier that stands above all those versions to identify the book rather than the various product formats it's delivered in. The ISTC (International Standard Text Code) was a good candidate, but as currently defined, it's only for textual works, and books increasingly contain non-textual content. Plus, it just hasn't gained any traction.
Authors also need to be identified unambiguously. There is often more than one author with the same name, and the same author's name isn't always stated the same way. This is a huge problem for academic authors: their income and status are dependent not just on writing articles and books, but for those works being cited. This has led to the development of ORCID, the Open Researcher and Contributor ID, which provides disambiguation of author names for scholars and researchers.
A similar solution has emerged for the rest of us: ISNI, the International Standard Name Identifier. What an ISNI identifies is the "public identity" of an individual or organization. Through metadata (how else?) the ISNI system "knows" that "Mark Twain" and "Samuel Clemens" are the same guy (but they have separate ISNIs, because those are two separate "public identities"), that there are two different authors named Richard Holmes who are both historians writing on similar subjects (each with his own ISNI), and it knows nine different ways that Maj Sjowall's name is spelled (all of which will be associated with the others via the ISNI).
The ISNI is also invaluable in disambiguating such things as the names of publishers -- and associating all of their imprints -- universities, corporations, and lots of other entities. The ISNI is new, but millions have already been registered. Once it is widely used it will be much easier for computers to keep things straight, and serve up the person or organization we're truly looking for. And, of course, the metadata associated with the author or organization is what makes such systems work.