How to Choose the Search Tools You Need from the University of California Berkeley. Meta-Search Engines from the University of California Berkeley. Try a Comparison Search - Try your search in 6 different search engines to easily compare the difference. They search the sites already indexed by the other search engines. Keyword searching is used to save time, but you also loose some possibilities for customizing your searches.
Search engines are programs that build indexes of the keywords or concepts found on web pages.
The index is built from Web wandererss, robots, spiders, crawlers and worms. You retrieve more results similar to a keyword search in an online catalog. Subject Directories are more like a subject search of an online card catalog. They are based on a thesaurus and help focus your search by limiting the number of sites indexed. This page is maintained by Patricia Rothermich , Reference Librarian.