They are often derived by analysis of the text of an item using entity extraction techniques or from pre-existing fields in a database such as author, descriptor, language, and format.
Thus, existing web-pages, product descriptions or online collections of articles can be augmented with navigational facets.
Faceted search interfaces were first developed in the academic world by Ben Shneiderman, Steven Pollitt, Marti Hearst, and Gary Marchionini in the 1990s and 2000s.
[3][4][5][6] The most well-known of these efforts was the Flamenco research project at University of California, Berkeley led by Marti Hearst.
[10] Examples include the filtering options that appear in the left column on amazon.com or Google Shopping after a keyword search has been performed.