Isn't this some kind of a math formula that by mistakenly landed in the SEO world. Yes of course it is but not by mistake, it just happened so as to aid us, the SEO's. Yes, it for true is gonna help us improve our rankings by showing the ways to further analyze the content and is developed so as not to manipulate the search engines but to work the way as search engines do. It definitely is a secret sword for those SEO's whose main objective is to work on, measure and improve the content.
I'm at where you're exactly now when I heard about this word TF * IDF, but be ready to get the complete knowledge of what this TF * IDF is all about and how as an SEO or website auditor or content optimizer you can get benefited.
So what is TF * IDF? TF * IDF is the acronym for Term Frequency times Inverse Document Frequency.
This TF * IDF is a measurement that combines both how many times a word appears in a particular page (TF) and how many times that same word appears in a list of all pages together (IDF), and is thus a weight which speaks about the importance of the word or term in that page.
Please click on the link below to get access to my document that gives a complete knowledge on TF * IDF, some case studies along with their results and some TF * IDF calculation tools.