I want to make sure I understand this right. My site is centered around a keyword that happens to be the name of a city. My site is a guide to that city, with hundreds of pages of content.
According to the term frequency-inverse document frequency model of text retrieval that most SE's use, that is, if I understand it right, I shouldn't use the name of the city in ANY of the site's pages (ideally) except the home page.
What I understand about tf-idf is that the more the word is used throughout the entire corpus (site) the higher the IDF and hence a lower overall relevancy score.