What is the difference between a Search Engine and a Directory?
The definition of the term search engine: "A program that searches
documents for specified keywords and returns a list of the documents where the
keywords were found." The term is often used to specifically describe
systems like Google, Teoma and Inktomi. These search engines typically send out
a spider to fetch as many documents as possible. Another program, called an
indexer, then reads these documents and creates an index based on the words
contained in each document. Each search engine uses a proprietary algorithm to
create its indices such that, ideally, only meaningful results are returned for
each query. (And we all know what that is like.)
In a directory this work is done by human editors. These editors check out
the Web sites before they are listed and give them a description that is fitting
for the site. Then these Web sites are placed into a hierarchical structure.
This makes it easier for an end user to find related topics and they also have
the option to place a query if they are looking for something specific and to
So basically the difference between a directory and a search engine, as used
in these terms, is that the first is human powered and the second is run by
means of robots with very little human intervention. Our users expect relevant
results with appropriate ratings and descriptions that let them determine
whether or not they want to view the site.