Google uses a special technology called PageRank that estimates an individual page’s value. Google assigns a web page a numeric weight, 0 -10. This number denotes that page’s importance within Google’s search engine. The higher the numeric number, the more usefulness of the page.
How the Google PageRank is calculated?
Google describes PageRank as, “..PageRank relies on the uniquely democratic nature of the web by using its vast link structure as an indicator of an individual page's value.” Each time a link from page A to page B occurs, then that individual page receives a vote. Google not only looks at the high volume of votes or links that a page receives. The page that casts the vote is also analyzed. Pages that are labeled “important” and weigh more heavily and help make other pages “important”.
Each page on the internet that links to your page casts a vote towards your page’s rank. The higher the ranking of the referring page, the higher page rank you will receive. In comparison, the lower rank of the referring page can also lower your page’s rank. To work around this issue, Google decides to exclude pages with a PageRank of 0 out of the calculation.
PageRank is often used by Web crawlers as a measurement to determine which URLs should be visited during the next web crawling. A majority of search engines also boost highly ranked pages in their search results. This in turn, offers highly ranked pages to be most visited.