A Search Engine Explained
With the widespread growth of the World Wide Web a specially designed tool to search through the information available was developed called the search engine. Using both algorithms and human editing the search engine will present results organized in a list consisting of web pages, information, links, and images. These results are viewed by the user after inputting a keyword or keyword phrase in to the search engines search field.
The search engines stores millions of pages of data available on the web and then uses different processes to deliver the most relevant data required by the users. Web crawling, indexing and searching are different processes that are used for the purpose and the order remains the same. The web crawler which is also known as the web spider works by scanning all the visible links. The web crawler, working as an automated web browser, examines all the pages and takes a decision on the indexing of the pages.
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 engines will examine keywords entered by the user and obtain a list of organized search results. Summaries may also accompany web links on the results page.
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.
Page rank is latest addition in the techniques used by search engines to sort out various web pages and their contents. Page rank decides the relevance of a particular page by studying the correlation between its meta tags, descriptions, keywords used and the content of that webpage. The search engines rank those sites high that have association with high ranked web pages. The page rank is essential for any web page or site as it determines its probability of featuring at the top of any particular search.
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