Keyword Density refers to the number of times keywords appear in the content of a page.
Keyword density used to be more important to the search engines. However, since keyword density is easy to manipulate, the search engines are now more interested in well written original content. Even so, you should make sure you have a good keyword density strategy in place.
Strategic keyword density involves the placement and repetition of relevant keywords throughout your content. You can not have too much repetition and the keywords must not be too close together (proximity) or the search engines may think you are spamming. You will also want to limit the use of non-target keywords.
Search engine experts vary in the way they calculate density. Some will use all of the words on a web page and others will exclude stop words or filter words in the total tally.
Many search engines have reported that they no longer use keyword density to determine the theme of a page’s content because density can be artificially produced easily. As a general rule, you should have appropriate keyword density because it is good for content relevancy and will help to service the needs of your visitors.
Luckily, there are some great websites with tools that can help you with your keyword strategy. One of the most commonly used websites is WeBuildPages.com.
Navigate to www.webuildpages.com/seo-tools/keyword-density to easily analyze the keyword density of your website. This tool will tell you how many times each keyword shows up in a block of content and the density percentage. As a rule of thumb, keywords should not be repeated more than 3 to 5 times per every 300 words of content.
Also you should optimize each page of text for no more than 2 keywords or phrases. Some SEO companies recommend optimizing only one keyword per page. You can also use this website to check out your competitor’s keywords.
Once you find out which of your competitor’s websites ranks #1 for a keyword you want to rank high for, look for words similar to that one that they are not optimizing for and optimize your website for that word.
Other websites that provide keyword density tools:
http://www.iwebtool.com/keyword_density
http://www.ranks.nl/tools/spider.html
http://www.seositecheckup.com