What should your keyword density be these days?
After you have chosen the keywords and keyphrases that describe your site and are of interest to your potential customers, the next step is to make your site keyword-rich and to have good keyword density for your target keywords. Keyword density is a common measure of how relevant a page is.
Generally, the idea is to find a keyword density that makes your page relevant to the search string you are trying to rank for, but to avoid simply stuffing your page with your keywords (as Google and other search engines will penalize you for that anyway). The recommended density is approximately 3 for the major 2 or 3 keywords and 1% or less for minor keywords.
Although there are no strict rules, try optimizing for a reasonable number of keyword phrases. Six to ten is about right. If you attempt to optimize for a list of 300 keywords, you will soon see that it is just not possible to have a good keyword density for more than a few keywords without making the text sound artificial and stuffed with keywords.
There are severe penalties (including search engine bans) for keyword stuffing because this is considered an unethical ‘black hat’ practice that tries to manipulate search results. It won’t work well today anyway, not when compared with strong local SEO tactics and an overall SEM strategy.