While you need to do some keyword research for proper search engine optimization, you also need to have the right keyword density in your website content. Density of a keyword in various elements of a webpage plays a big role in optimizing your site. By using keyword density analyzers you can check out your sites keywords plus those of your competition to potentially boost your online income. Many great online tools are available to check keyword density, including prominence and placement, keywords in page elements, outgoing and incoming links, and filtered words, while others are even more sensitive.