Merchandising relies on ATG Search to generate facet sets. You define facets in Merchandising, but it is ATG Search that determines whether a facet applies to a set of products or SKUs. When page developers create Web site pages that display facets, they display the facet selection values as hyperlinks. When a customer clicks one of these links, a query is issued to ATG Search, using the faceting property as a refinement criterion. For example, a customer might perform a search that returns a set of products that are displayed on the page. If the customer then clicks the Sale Price facet’s “$100 to $200” link, a new query is issued that specifies “return only the products in this set whose sale price is between $100 and $200.” The results of this query are then displayed on the page, and the facet selections are updated.