Search Engine Optimization is a function which makes a website or any particular information from a website to appear forefront when a person tries to reach at the desired pages or website with the help of key words on different Search Engines like Google, Yahoo, and MSN.  The websites providing services, products or online shopping are the main entities to depend upon SEO.  SEO function revolves around  organic and inorganic applications, link exchange, improved contents of website, quality of information about products and services, perfect choice of key words etc. etc. depending upon the present status of website.  When SEO functions are in full swing then there are great chances of SEM (Search Engine Marketing) resulting in new avenues of income by way of link exchange and advertisement etc.