How does Google find the top keywords of your website?
All major search engines index web pages based on the individual words that they find on the page. If certain words and phrases appear together on the same page, search engines assign a topic that is related to these words to the page.
For example, the words “Paris” and “Hilton” are associated with a woman instead of a city and a hotel, the words “Tiger” and “Woods” are associated with golf.
Google’s patent application indicates that Google might plan to tell you what they believe are the top keywords for your website and let you suggest changes to these phrases.
How can Google find the relation between words?
Google has billions of web pages in its index. If Google finds that many web pages contain both the word “Paris” and the word “Hilton” then Google might assume that these keywords are related. The other words on these pages could give Google a hint that this special word combination is about a woman.