What is the difference between Keyword Density and Keyword Stuffing?

Keyword Density

Simply put, keyword density is the number of times a keyword is used on a webpage divided by the total number of words on the page.  It is important to remember, too low keyword density and the search engines will deem your page w irrelevant; too high and the engines will find your site "spammy" and trying to artificially increase the relevance of the page.

Keyword stuffing 

"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.

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