In order to place the proper stress on secondary keywords, it is necessary to place them in context by drawing a comparison and contrast between it and primary keywords. But before that, we must regress by just one step and remind ourselves that the reason there is primary, secondary and keyword density issues is so that a machine can determine without prejudice and appreciation of poetry what the content is about. In prose, it is possible for someone to write all kinds of words and insinuate the message, sometimes to greater effect. But if the same was done for a bot to understand, the effect will be infinitely lost. As such it is for the machine that a formula is derived to define the article by keyword, both primary and secondary.
The primary keywords places the article or blog in the ballpark. Ideally it should be the keyword that you wish to rank on the engines. If a dentist were to write about fillings, the topic may be about fillings, but if he wants that article to count towards his keyword choice, ‘Dental Prosthetics’ for instance, then the article will have to be sculpted within the mold of dental prosthetics and refer to fillings in a different way.
Secondary keywords are used in an article to allow the article to take shape. In other words if primary keywords are the meat, secondary keywords are the flavor. Like a dish, Beef Bolognese – beef is the meat, Bolognese is the flavor. Applying this to dentistry, we combine the keywords in a different way, the do not need to reside adjacent to one another but appear in places that complement the other.
Applying a more accurate example would be to arch an arrow. The arrow is the primary keyword, the trajectory of the arrow is the secondary. It is the secondary keyword that gives the primary keyword meaning and context. Beef on its own, is just a slab of meat, make it in Bolognese it becomes a meal. An arrow is just an arrow until it is catapulted on a trajectory toward its target.
The secondary keywords place the primary keywords in context. For example, imagine you are writing for your dental practice and it has been decided that the keyword target is ‘dentist’ however there is no secondary keyword chosen. Among the many interdisciplinary aspects of dentistry, how would an algorithm be able to decipher how to categorize the article. A secondary keyword in various places in the article, for instance, ‘children’ will alert the algorithm that the topic has something to do with dentistry in relation to kids.
Ideally, articles should be either written by a professional writer or by the dentist himself then vetted by a SEO writer to make the script more appeasing to the bots.