We tend to have a very record-based view of bibliographic systems. Searches in a resource result in lists of record-based displays for items. All fields may not be indexed. This means that the data works less hard than it might, given the variety of ways in which it could be leveraged to tell us more about the body of literature a resource relates to.
The introduction of facets changed this a little. In Worldcat Identities we are interested in bringing together a view of parties who create or are the subject of works.
My colleagues have now worked with the Worldcat.org team to provide a view of Worldcat by genre.
For some more details see the project page.
The project applies principles of the FRBR model to aggregate author and title information and statistical association techniques to generate related subject headings (e.g., topics, characters, people, places, and organizations). The initial set of profiles is based on genre terms selected from the Guidelines On Subject Access To Individual Works Of Fiction, Drama, Etc. (GSAFD), 2nd edition. Genre definitions are adapted from scope notes in GSAFD, and the Library of Congress authority file and Moving Image Genre-Form Guide. More genre/form profiles will be added over time. [Worldcat genres]