Search Engine Plays an important role in SEO. Before an understanding of SEO, first, we know about Search Engine works. How Search Engine shows result in search page according to the user search. There is some activity performed by Search Engine:
Crawling is performed by special software which is called Crawler or Spider. Crawlers fetch all pages which are linked to a website.
After Crawling indexing process is beginning. In this, all fetched web pages index is created and keep them in a massive database so that retrieve it later. The process of indexing is identifying the words and phrases that best describe the best page of the website and assigning the page to particular keywords or phrases.
When a user enters the search request in search engine, then search engine process it, i.e. it compares the Search requests of the search engine with the indexed pages in the database. More than one page contains search String in the database, and search engine finds the relevancy of string which is present in indexed pages of a database.
The last step in the activity of Search Engine, to retrieve better result according to a search request. It is nothing just to display the accurate result in a browser window.
All search engines such as Google, Bing, and Yahoo updates their algorithms several times in a month. When anything is changing in your search ranking it just causes of searching algorithms.
All the functionality of search engines is a same only difference in just their relevancy algorithms and that may change their search ranking of websites. The crawler is very intelligent they easily find the duplicate content of a website. So avoid using duplicate content on your websites.