The importance of the written text on your website pages cannot be over-emphasized. It must contain the proper keywords for effective SEO without compromising vital relevance for visitors to your site. I always write for visitor relevance first and optimize the text second because it is the relevance of the information presented that will keep visitors on the site and give you the chance to convert them to paying customers. If text relevance is weak, the odds are good that the visitor will go elsewhere. The balance between relevance and keywords must be proper to earn high search directory rankings and retain visitors.