In order determine, which pages will be displayed higher for the keywords entered, search engines follow a method called an algorithm.
Algorithm used by Search Engines
An algorithm is a mathematical formula, which has been written in a step-by-step manner. This algorithm determines the results based on the keywords that the search engine has compiled.
You can think of an algorithm like a number-crunching machine. It is a complicated formula that arranges information into a more useable format.
Once the user enters all the data into the algorithm "machine", the algorithm starts sorting the information it already has in its bank, and starts delivering the most relevant results.
In this case, the result is the ranking of websites that are indexed by the search engine, based on the keyword, which the user entered into the algorithm "machine."
Search Engines can Rank Websites depending on Quality
Search engines use a complicated formula in order to determine the best quality websites online, without having any human intervention. They can rank site’s quality without the help of any human.
The basic job of the search engine is to provide the closest and the most relevant match, to ensure that users keep coming back. Relevancy is the most important aspect of SEO.