I use search facets in a number of contexts everyday.
But today this summary from Wikipedia struck me differently than most days:
A faceted classification system allows the assignment of an object to multiple characteristics (attributes), enabling the classification to be ordered in multiple ways, rather than in a single, predetermined, taxonomic order. A facet comprises “clearly defined, mutually exclusive, and collectively exhaustive aspects, properties or characteristics of a class or specific subject”.[1] For example, a collection of books might be classified using an author facet, a subject facet, a date facet, etc. (From Faceted classification at Wikipedia.)
My general experience is that facets are used to narrow search results. That is set result set is progressively narrowed to fewer and fewer items.
At the same time, a choice of facets can be discarded, returning to a broader result set.
So facets can move the searcher up and down in search result size, but within the bounds of the initial result set.
Has anyone experimented with adding facets from a broader pool? Say all the items in a database and not just those items in an initial search query?
Enabling the user to “drill out” from what we think of as the initial result set?
Which would raise questions about managing facets for a changing underlying set. For a user to broaden or narrow the result set in the more traditional way.