Though it is really a good approach of using synonym keywords instead of keyword stuffing but it appears a bit confusing about how to calculate actual keyword density of keywords used in the body.

It is said that keyword density is important in terms of setting the relevancy of the page with the search terms then the question arise is how can we calculate the weight of the page in terms of keyword density when using synonym as keywords.

For example – If I am using keyword “Yoga for pregnancy” 5 times per 100 words then it stands as 5% but what if I am using the synonyms “Yoga for pregnancy” 3 times and “Prenatal yoga” 2 times.

Does it makes a complete keyword density of 5% for prenatal yoga and yoga for pregnancy as well or it individually stands as 3% and 2% for their respective density?

As we all know that previously everyone would like to pay more intention for a single more common keyword to rank in SERP, but practicing that strategy is nothing but ignore huge traffic that comes in small numbers from different keywords that are synonymous.

So, synonym keyword use not only increase the chance of getting found by lots of other users but also helps us get rid of risk of google penalty due to keyword stuffing and helps in increasing the relevancy of the page.

@Tim: Like David said in the article, use semantic words

Does anyone have any advice on how to get around this annoying issue?

I should have mentioned Yahoo and Bing, and didn’t even think of it. But it is true that neither one use synonyms, and I have heard their stemming is not near as complete as Google’s. However, since 70%+ of searches are done on Google, I think it is a good practice to consider for any website.

The spoilers here are Yahoo and Bing, which do a much poorer job of stemming than Google. For example, it’s not uncommon to see oneself on page one in Yahoo for the singular of a noun, but dozens of position below for the plural of the same word (or vice versa), let alone anywhere in the same ballpark for more complex word relationships.

A note that alt attributes offer excellent opportunities for using synonyms, especially when you’re forced to use the “correct” for of the word in copy. For example, the annual NFL championship contest is the “Super Bowl” yet users search equally for “Superbowl”. Adding a “Superbowl” alt to your Super Bowl page image header, pointing an internal image based “Superbowl” link and, if possible, an external text anchor will give you plenty of juice for the synonym. Just sticking to “Super Bowl” alone won’t give you what you need to rank for “Superbowl”, especially in second-tier (non-Google:) engines.