That's obvious isn't it? It's an important word? In fact that's rather understating the degree of importance associated with Keyword in search engine marketing terms.
In order for the search engine indexes to offer your web page as a relevant result to searching customers, this word or phrase MUST appear visibly in your site and ideally in the source code of your web page. Webcertain will undertake all the research and planning necessary to identify Keywords for you - and this information is contained in a Keyword Map which is plan for which Keywords are to be seeded into which pages for the best results for your site.
Unscrupulous sales organisation often tell you they can offer you Keywords in the major search engines. They are talking about using the same words or phrases in pay per click campaigns - when they do NOT have to be contained in your site.