To look for information on the Internet, one would use a search engine. The results of any given search are typically presented in a list on a web page with a title, description of the result and a link to the result. “Hits” is the name generally given to the list of results. The results can be varied in their content, ranging from web pages, to images and videos, scholarly articles and web pages with links to other web pages. Search engines typically use various algorithms to find the material that is requested.
The way a search engine operates is through a web crawler. First, the search engine keeps information about many web pages using the HTML inside those pages. Then the crawler goes through those sites in a methodical and orderly fashion, following all the links on the sites. The downloaded pages or results are indexed for faster retrieval. For example, Google stores all or parts of web pages as well as information regarding the web page while Altavista stores all the words of all the pages it finds. These stored pages are referred to as a cache and are indexed and updated for when a term that was searched on is no longer part of the content. This means of increasing the relevance of the search is very useful and important to the workings of search engines.
The relevance of the list of results determines the usefulness of a search engine. There could be a large number of web pages that contain the words queried in the search engine but some of the results may be more relevant than others. Most search engines list their results in some kind of rank so that the results that match the query the best are displayed at the beginning of the list. How the search engine determines which results are most relevant depends upon the search engine itself and the technology it uses to determine the rank.