How to work search engines?

[Shane Bentick]

Search engines have two major functions: crawling and building an index, and providing search users with a ranked list of the websites they've determined are the most relevant.Links allow the search engines' automated robots, called "crawlers" or "spiders," to reach the many billions of interconnected documents on the web.Once the engines find these pages, they decipher the code from them and store selected pieces in massive databases, to be recalled later when needed for a search query. Search engines are answer machines. When a person performs an online search, the search engine scours its corpus of billions of documents and does two things: first, it returns only those results that are relevant or useful to the searcher's query; second, it ranks those results according to the popularity of the websites serving the information.