I’ve just read this interesting article about faceted search: http://www.uie.com/articles/faceted_search. Faceted search or guided navigation allows you to search by different types of metadata (called facets). You can drill down via these dimensions: narrow down your search result by selecting the value you prefer in the choice lists associated with these facets. Or search for related items, which share facets.
Personally, I use the faceted search feature in an online bookstore I visit: I browse the collection by selecting a category, a genre, a price range, a language, or whichever suits my needs at that moment.
Stephanie Lemieux lists in her article a set of dos and don’ts that have emerged as best practices for designing faceted search.
