The idea under discussion is that, since the Hummingbird algorithm update in 2013, Google is getting really good at understanding natural language. So much so, in fact, that it's now able to identify similar terms, making it less important to worry about minor changes in the wording of your content in order to target specific keyword phrases. People are arguing that it’s more important to think about the concepts that Google will interpret, regardless of word choice. Moz wanted to see how true this is now, in the present. So it designed an experiment. The question it wanted to answer was: “Do searches within the same topic (but with different keyword phrases) give the same result?” The results revealed that targeting individual keywords is definitely not a thing of the past. For most of the topic groups, the pages that rank in the top 10 have little consistency across different wordings of the same concepts. From this we can assume that the primary thing making one page rank where another does not, is matching exact keywords. Get the full story at Moz