Though a unique content is very important in Search Engine Optimisation (SEO) and density importance in SEO is vital to the page ranking of a site. One of the most effective strategies in boosting the page rank of a site is keyword density. Keyword density, in a nutshell, centers on the number of keywords or keyword phrases included on a webpage in relation with the number of words. When writing contents, one should remember to place keywords and keyword phrases naturally throughout the entire content. It is important that one should avoid keyword stuffing where too many keywords are placed on contents. Major search engines see keyword stuffing as a black hat SEO strategy. If you are caught keyword stuffing, your site will be banned from the search engine index.

It is said that the recommended keyword density should be between 4 and 8-percent. This suggests that for a 500-word article, 20-40 keywords included all throughout the content is just right and won’t let you get penalized. Personally, 5-percent keyword density is more than enough, working well for all the articles I have written in the past.

Aside from keyword density, keyword proximity should also be considered. Keyword proximity is about how close keywords appear to each other all throughout the entire content. See example below.
Keyword: Internet Marketing Strategy:

1. An Internet marketing strategy is essential for online businesses.
2. Online businesses wanting to have a strong presence on the Internet require a
good marketing strategy.

Notice that while the first sentence has the keyword put together, the keyword on the second sentence got separated. Theoretically, the first sentence is expected to rank better in the major search engines than the second one. Remember that though content is king, keyword proximity and density is also of prime importance to SEO.