Search Engine Optimisation is as important as your website design and html. Without it, you website might not be found for under the key phrases looked for in search engines like Google and Yahoo.
SEO is process of optimising website , updating content, Selecting a proper keywords and phrases and the positioning of them. If you get this right, you start to improve your chances of getting on the first page in search engines when someone search for selected keyword. With good SEO, your website will rank better in search engine like Google, Yahoo and Bing.