How Search Engine Works ?
Search engines perform these activities to deliver search results.
A Search Engine is a web or internet software system, which is designed to carry out web search or Internet search for the content through the World Wide Web (www) in a systematic way for particular information specified in a web search query.
Google is a fully-automated search engine that uses software known as “web crawlers” that explore the web on a regular basis to find sites to add to its index.
The vast majority of sites listed in google results aren’t manually submitted for inclusion, but are found and added automatically when google web crawlers crawl the web.
Crawling – This is the Process of fetching all the web pages linked to a website. This task is performed by a software, called a crawler or a spider (or Googlebot, in case of Google).
Indexing – Process of creating index for all the fetched web pages and keeping them into a giant database from where it can later be retrieved. Essentially, the process of indexing is identifying the words and expressions that best describe the page and assigning the page to particular keywords.
Processing – When a search request comes, the search engine processes it, i.e. it compares the search string in the search request with the indexed pages in the database.
Calculating Relevancy – It is likely that more than one page contains the search string, so the search engine starts calculating the relevancy of each of the web pages in its index to the search string.
Retrieving Results – The last step in search engine activities is retrieving the best matched results. Basically, it is nothing more than simply displaying them in the browser.
When a user performs a Google search, Google tries to determine the highest quality results. The “best” results have many factors, including things such as the user’s location, language, device (desktop or phone), and previous queries.
For example, searching for “Mobile repair shops” would show different answers to a user in India than it would to a user in Florida. Google doesn’t accept payment to rank pages higher, and ranking is done algorithmically.