Search engine traffic of the i think best for the adsense, because people finding keywords always use fully your site or blog and thus adsense earning increases. only 2 unique users yesterday hit more than 100 pages views to my site of mysite. SEO TIP: keep main keyword of your site or blog about 10-15% of the total page matter, rest lower 7-10%, rest lower than that and only fight for not more thatn 3-4 keywords. It will give you good ranking in google.
10% - 15% keyword density will get your site flagged for keyword spamming. you might get an initial boost, but over the long run, your site will be penalized