A professional-looking design is important for a successful web site, but it does not end there.. Equally important is site content.

Web Site SEO (Search Engine Optimization) : is the process of improving the visibility of a website in search engines such as Google, Bing, Yahoo and others via the "natural" or un-paid ("organic" or "algorithmic") search results.

In general, the earlier (or higher ranked on the search results page), and more frequently a site appears in the search results list, the more visitors it will receive from the search engine's users.  

SEO considers how search engines work, what people search for, the actual search terms typed into search engines and which search engines are preferred by their targeted audience. Optimizing a website may involve editing its content and HTML and associated coding to both increase its relevance to specific keywords and to remove barriers to the indexing activities of search engines.

" http://en.wikipedia.org/wiki/Search_engine_optimization"