These components allow the entry of a user-defined query (e.g., a search) and automatically present users with a customized set of results that match their queries. Think of these as dynamic and mostly automated counterparts to browsing aids. Types of search components include:
Search interface
The means of entering and revising a search query, typically with information on how to improve your query, as well as other ways to configure your search (e.g., selecting from specific search zones).
Query language
The grammar of a search query; query languages might include Boolean operators (e.g., AND, OR, NOT), proximity operators (e.g., ADJACENT, NEAR), or ways of specifying which field to search (e.g., AUTHOR=“Shakespeare”).
Query builders
Ways of enhancing a query’s performance; common examples include spell checkers, stemming, concept searching, and drawing in synonyms from a thesaurus.
Retrieval algorithms
The part of a search engine that determines which content matches a user’s query; Google’s PageRank is perhaps the best-known example.
Search zones
Subsets of site content that have been separately indexed to support narrower searching (e.g., searching the tech support area within a software vendor’s site).
Search results
Presentation of content that matches the user’s search query; involves decisions of what types of content should make up each individual result, how many results to display, and how sets of results should be ranked, sorted, and clustered.
Site Administration 
