Searching software enables users to query the index of files and usually return results in a relevancy ranked order. Note that you are not searching the Internet live as it exists at this very moment. Instead, you are searching a fixed database that has been compiled previous to your search. When you have a narrow topic or idea to research When you are looking for a specific site or known document When you want to retrieve a large number of documents on your topic When you want to search for particular types of documents, file types, source locations, languages, date last modified, etc. Directory services use selection criteria for choosing links to include, though the selectivity varies among services.
Most directories offer searching software to enable users to query the list of files.
They emphasize popular subjects, which are not covered by most academic directories. They are also referred to as parallel search engines or multi-threaded search engines. Read the directions at each search site. The technique for formulating a search depends on the search tool you are using. There is a wide variety of options available among the different search tools.