Keyword dilution is a term used to describe when the spectrum of keywords on a page doesn’t relate to each other to tell search engines what content is really about.
We can also define it as using a group of keywords that do not complement each other to cross-optimize content, but rather dilute the impact of each other on the page.
For instance, if you have content that is targeting a keyword but at the same time targeting some other keywords not related to your main topic may be a good example of keyword dilution.
If your content is about Golden retriever dogs, it should clearly tell Google you are writing about it. By changing the discussion occasionally to another topic such as red apples or bergamot oranges you may distract Google from assigning relevancy to your content.
Using new words in our content is fine. I don’t see any problem with that.
However, if we progress our content around multiple terms we are likely to create a keyword dilution effect. Because using a term quite enough time will create a keyword effect for that specific term.
You cannot optimize a page for so many keywords because the more keywords you use, the less important other keywords become.
The reason for it is quite simple.
Search engines use natural language processing. Although they are getting better by using AI and machine learning, they can still only read what you have given. If you give mixed messages or if your keywords are diluted then they will not understand what your content is really relevant to.
Let’s say you have a content targeting the keyword “grooming dogs”. If you include all other keywords like “dog nutrition” or “dog walking” you automatically dilute the effect of your main keyword.
Because after including all-new keywords our content turns out to be a general informational writing rather than a keyword-targeted content.
It is always a good idea to focus on no more than 2-3 keywords for any piece of content we create. More than that is likely to bring any benefit but create keyword dilution for our content.
Let’s have a look at another example. Here are 3 keywords assumed as targeted keywords in a piece of content.
Sleeping bags 100%
Sleeping bags 65% + Sleeping pads %35
Sleeping bags 50% + Sleeping pads 25% + Sleeping equipment 25%
More keywords we bring in our content, the more the main keyword dilutes. The keyword sleeping bags will dilute if we introduce sleeping pads or sleeping equipment as secondary keywords.
Keyword stuffing can also create a keyword dilution effect on the content.
Let’s say you have a keyword and you repeat it everywhere on your page in the title tag, meta description, image alt tags, and headings. It doesn’t only dilute your keyword due to keyword stuffing but may also trigger the webspam algorithm against your content.
Some people prefer closing comments section on their pages to keep the keyword consistency on their pages. That may also be right on-page SEO practice because sometimes comments on a page can be longer than the actual content.
Keyword dilution is an important consideration for content marketing. If neglected it can negatively affect search engine rankings.