What is the Best keyword density for a page 
What is the best Keyword Density for a page for SEO?
This question has been asked at some point in time by most SEO Analyst, web marketers, copywriters, and anyone else who puts text on a website. While no search engine comes right out and says what the best keyword density is, I have worked with enough website to have an idea of what works and what does not.
You have to be careful about keyword density as not to go too high or search engines can discount your site because it becomes to spammy. I have found that if you a keyword density for a specific keyword phrase between the 2-3% range you will be ok. It is better to have more instances of the keyword on the page up to a point. You want to have more exact matches but in order to keep the density low you have to increase the volume of text on the page.
I have found that having between 300-600 words on the page will allow you to have a low enough keyword density but still allow you to have enough multiple exact matches to your targeted phrase to be competitive given you have enough Page Rank distributing to that page. You also typically don’t want to focus a single page to more than 2-3 highly competitive keyword phrases. The page will automatically get found for more “long tail” keyword phrases as well if you can generate enough unique content to fill the 300 word minimum.
Brad Henry
Search Engine Optimization Analyst
www.seoslap.com