A search engine is a device that delivers contents to you as per your query from the World Wide Web. Search engine locates the suitable content from the plethora of information available on WWW in form of links, images and web pages. These engines are based on complex algorithms and sometimes even on human editing.
A search engine uses web crawling, indexing and searching in that order to provide the most accurate results related to a particular search. Search engines work by storing information about millions of web pages that can be retrieved at the request of its user. The web crawler, or “spider,” is used as an automated web browser. It follows every appropriate visible link. The web crawler analyzes the contents of each link to determine how the pages should be indexed.
Words found inside the pages are extracted from the description and allocated appropriate meta tags. Meta tags are also taken from contents the webpage itself to establish its relevance. Data from the sites is collected, indexed and stored to be retrieved when it’s needed.
Companies such as Google store all or part of the source web page, while AltaVista stores every page word for word. The information stored and indexed is known as the cache, it allows for instant updating and keeps the searching filtered with ease. An important factor for a successful search engine is its ability to provide active and useable information with minimal to no linkrot. The cache also saves an archive of a removed source that can later be access by the user after the site is updated.
Search engine users normally input a keyword or key phrase into the search field. The engine will search for their particular keyword and key phrase on the World Wide Web. The search engine index will provide an organized list of results with the best matched web pages. A short summary of each webpage describing the contents is provided along with the list.
Many filters and specialized web crawlers create a proprietary method for analyzing web pages for results. While a keyword can be found a very large amount of websites not all sites are relevant to the users purpose and companies pride themselves on result relevancy.
Some search engines use page rankings to assist in their sifting. The search engines look at each individual page and determine through their meta tags, descriptions, keywords and content if the sites are relevant based on the key words in the search. The higher a site is ranked, the higher to the top of the results inventory it will be. The search engine sometimes uses other websites to help determine how highly a site should be ranked. If your page is linked to a higher page, it means that your page will have a higher rank in the search outcome.