Search
http://www.usability.gov/pdfs/chapter17.pdf

Usability.gov
2006

Abstract:

Many Web sites allow users to search for information contained in the site. Users access the search capability by entering one or more keywords into an entry field--usually termed a 'search box.' When there are words in the Web site that match the words entered by users, users are shown where in the Web site those words can be found. Each page of a Web site should allow users to conduct a search. Usually it is adequate to allow simple searches without providing for the use of more advanced features. Users should be able to assume that both upper- and lowercase letters will be considered as equivalent when searching. The site's search capability should be designed to respond to terms typically entered by users. Users should be notified when multiple search capabilities exist.