"SEO or Search Engine Optimization is "a process of affecting the visibility of a website or a web page in a search engine's "natural" or un-paid ("organic") 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 may target different kinds of search, including image search, local search, video search, academic search, news search and industry-specific vertical search engines".
A lot of people still does not understand what SEO is even though the said internet strategy has been around since the early incarnations of search engines. Working as an web designer/ webmaster and SEO specialist for quite sometime now I can share my two cents on what is SEO all about.
If we go over to wikipedia:
Unlike Web Designing, Graphic Designing or Web Development on which once a website is built, you can now turn over the project to the client, SEO is an ongoing process since every website has its own degree of online presence, the better we do SEO to a website, the better we maintain his visibility on the first pages of each major search engines.