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Web Terms
Web Terms
What is a Search Engine?
A search engine is a coordinated set of programs that searches for and identifies items in a database that match specified criteria. Search engines are used to access information on the World Wide Web.
How do search engines work?
Google is the most commonly used internet search engine. Google search takes place in the following three stages:
Crawling
Crawlers discover what pages exist on the web. A search engine constantly looks for new and updated pages to add to its list of known pages. This is referred to as URL discovery. Once a page is discovered, the crawler examines its content. The search engine uses an algorithm to choose which pages to crawl and how often.
Indexing
After a page is crawled, the textual content is processed, analyzed and tagged with attributes and metadata that help the search engine understand what the content is about. This also enables the search engine to weed out duplicate pages and collect signals about the content, such as the country or region the page is local to and the usability of the page.
Searching and ranking
When a user enters a query, the search engine searches the index for matching pages and returns the results that appear the most relevant on the search engine results page (SERP). The engine ranks content on a number of factors, such as the authoritativeness of a page, back links to the page and keywords a page contains.
