Keyword Density & Keyword Proximity
There has been quite a bit of discussion recently regarding keyword density, a meausure of how often a keyword or keyphrase is repeated throughout the course of an individual page. Oftentimes within SEO circles, the topic of keyword density returns and it's best to address it, as it tends to be one of those topics that the charlatans of SEO often latch on to, citing it as a major factor in ranking. Clearly, keyword density did once play a role (although it is difficult to determine how much) once, but whether it plays a role today is anyone's guess. I set out to do some research on keyword density but what I found surprised even me. Using the Webconfs keyword density checker (http://webconfs.com/keyword-density-checker.php) however I found that more important than density was that the actual positioning of search terms played a greater role than the actual percentage density.
I deciced upon pretty much the most obscure search phrase I could come up with - tomato soup recipes - which receives in the neighborhood of 20K searches each month according to Google's External Keyword Tool.
Keyword Cloud is a visual depiction of keywords used on a website, keywords having higer density are depicted in a larger fonts.
Ideally your main keywords should appear in larger fonts at the start of the cloud.
Keyword Density is the percentage of occurrence of your keywords to the text in the rest of your webpage.
It is important for your main keywords to have the correct keyword density to rank well in Search Engines.