What is the fine-grained topic of the following text: So that's the keywords density concept and it play very important role in seo, because search engines organize webpages into different categories so keywords density can take your site to good category and can also bring good guality advertisement , like if donate keyword have max density then google and other advertising company will display charity related ads on your webpage. Only return the topic.
Keyword Density in SEO and its Impact on Website Categorization and Advertising