SEO starts with understanding how Search Engines operate. There are 4 key functions that search engines such as Google, Bing, Yahoo, etc.. perform. Those are
- computation of relevance and ranking
- producing search results
Crawling is the process of search engine in which automated robots called as “crawlers” or “spiders” read all the interconnected documents of a website/page through links.
Search engines parses the code in the web pages found through links and stores the important/ relevant pieces to enable retrieval of relevant data when queried (searched) by a user. This process of storing relevant pieces of data is called indexing.
As of September 2014 internet has over 1 billion live websites, now wonder how would a search engine decides what it should display for the user entered search query. Well search engines have built complex algorithms which will decide the relevant websites, rank them based on quality of content and popularity and display the results to the user.
TIP: It is believed that google uses over 200 factors to arrive at the page ranking