This is a service that offers a collection of links to Internet resources. The links are submitted by site creators or site evaluators and they are organized into subject categories. Most subject directories offer a search engine mechanism to assist the user in finding information within the directory. Subject directories are created by humans and contain smaller databases of information than true search engines. Indexing of the database is created from the collected files and little if any selection criteria is used in the collection of the files for the database.
Search engines contain all of the files that exist on the Web.
The information on the Web is expanding rapidly and search engines and subject directories simply cannot keep up. In addition, information contained within databases in denied to search engine spiders. An increasing amount of information posted on the 'Net is contained in databases. Both tools, the subject directory and the search engine, should be used when doing any research involving the Internet. Each serves its own purpose.