If you are working on "Google Adsense" earning program and your monthly income is more than 200$, it meanz you must have sufficent knowledge of SEO(Search Engine Optimization).
When you create your site. It needs to b optimized. Because new site cannot index itself in search engine directries,because every search engine has its own terms and condition to index your site. And your site PR(Page Rank) is also an important issue, and to get reasonable traffic, your optimization work will b very focused. How much you are familier with search engines, that is search engine optimization