Introduction to SEO What is a SEO and why it is used? SEO stands for search engine optimization and it is used for purpose of ranking a website in search engine results. Search Engine is a software program to search anything on internet. Eg. Google, Bing, Yahoo, etc. SEO also make website more understandable for search index bots for indexing purposes. If a website is higher in rank in search result then more users will visit this website, and if it has low rank in search results then less users will visit this website. This is because search engine rank website according to time spent and no. Of users visited website. Depending on this websites are ranked in search engines.