As Google continues to refine its algorithm, one area which needs more emphasis, is the overuse of a keyword or keyword phrase on a given web page. Although Google has not come out and specifically given a number or percentage that a keyword should appear on a page, they have said that keyword stuffing or spammy keywords are against their guidelines.
Google’s guidelines say: “Keyword stuffing” refers to the practice of loading a webpage with keywords in an attempt to manipulate a site’s ranking in Google’s search results. Filling pages with keywords results in a negative user experience, and can harm your site’s ranking. Focus on creating useful, information-rich content that uses keywords appropriately and in context.”
A good service to use with your SEO efforts is SEOMoz.com, a leader in the SEO world. They state, “We’ve seen evidence that excessive use of keywords can negativity impact rankings and thus suggest moderation…remove instances of the targeted keywords from the document text to bring the level below 15 occurrences.”
It is important to pay attention to the spammy use of keywords onyour web pages. A good tool that can be downloaded for determining how many times a keyword is repeated on a given page is: http://www.seoquake.com/ Once downloaded, use the “keyword density” part of that tool to see how many times a keyword or phrase is repeated.
Basically, you need to write your content so that it is written for the user and not search engines. It needs to flow naturally, without a lot of repetitive use of a word or phrase.