Keywords are very important tools when it comes to search engines. They help web crawlers to analyze the relevance of particular webpage. The frequency of these keywords on a particular webpage in agreement with the total count of words on that webpage is called keyword density.

While some of the search engines such as Yahoo allow greater keyword density (up to 5%), there are search engines such as MSN Google that prefer limited number of keywords (maximum 2%). The site has to abide by this limit in order to avoid suspicion of spamming.

However, there is nothing certain that can be applied as an ideal keyword density as the algorithms of these search engines change frequently. There are some search engines that stress more on the use of keywords in Meta tags, title, and in the web copy, while others such as Google favors keywords in the text of the web page.

Perfect keyword density varies according to the nature of used keywords as well. While one very competitive keyword is considered more than enough for a single webpage, on the other hand for the less competitive ones frequency of 2-3 is believed appropriate.

Generally 2%-5% of keyword density is considered optimum for a single webpage. One keyword for one webpage is believed to be best for higher SEO ranking. If the keyword density is very high, search engines will assume it keyword stuffing and can penalize your website for spamming. Therefore the best approach is to strike a natural balance.

It's also very important to understand that keyword density is used for per webpage and not per site. It's also essential to place keywords at least in all the headlines and first and last paragraphs of the webpage content.

While writing content for your webpages, it's very important to understand that you are writing articles for the visitors and not for search engines. People generally use search engines tactics while creating content for webpages while the motto should be our visitors. If you forget the potential visitors, nothing can make your website a success.