Search engine optimization (SEO) is a set of methods aimed at improving the ranking of a website in search engine listings, and could be considered a subset of Internet or Web marketing. The primary purpose of SEO is to get higher rankings on search engines which in turn creates a larger target audience.
To quickly get an idea of what the challenge is in SEO, just type a search term into Google. Enter it without quotes because that is the way most users perform searches. You will get back a page of search results and an estimate of the number of pages on the Web that are indexed for that specific search term. That number represents your site’s competition for that particular search term.