SEO Best Practices
Relevance is viewed in terms of densities; the higher the density, the higher the relevance. However, there is a tipping point wherein the text gets over optimized. Think of a fish bowl. The more fish in the bowl the denser they are. Too many fish and they die due to lack of oxygen. The same goes for a web page. Hitting the right densities is goal in optimizing a page. Note that in calculating content density, Head elements such as Title and Meta tags are not counted.
There are two (2) types of densities. Phrase Density where the instances of the phrase are counted and Aggregate Density where the sum of the individual words in the target keyword phrase is counted with respect to the total content.
Based historical data, the sweet spot for page word count has diminished from 700 to 900 words, favoring less content of 400 to 500 words. Note that all words on a page are counted toward density; this includes text in banner, navigation and footer sections. When creating a webpage please take in to account the whole page in the body section of the HTML document.
Note: Page densities are inversely proportional to word count. The higher the word count, the lower the density and vice-versa. The lower the word count the higher the densities can be.