On the Internet, a search engine is a coordinated set
of programs that includes:
A spider (also called a "crawler" or a "bot") that
goes to every page or representative pages on every Web site that wants
to be searchable and reads it, using hypertext links on each page to discover
and read a site's other pages
A program that creates a huge index (sometimes called a "catalog")
from the pages that have been read
A program that receives your search request, compares it to the entries
in the index, and returns results to you
An alternative to using a search engine is to explore a structured directory
of topics. Yahoo, which also lets you use its search engine, is the most
widely-used directory on the Web. A number of Web portal sites offer both
the search engine and directory approaches to finding information.
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