I read a great article by Michael Templeman explaining the Google RankBrain SEO implications.
So what is Google RankBrain? This is Google attempt at machine learning in which RankBrain makes correlations on search queries to improve results, especially for slang, new searches, and trending content. It is artificial intelligence that has been put into the Hummingbird search algorithm.
While RankBrain is not full machine learning it makes ranking factors much more complicated.
“Google has said that they consider the signals coming from RankBrain to be the third most important signal they base their rankings on.”
So what does this actually mean for SEO? If you are trying to “game” Google search rankings your job just got much more difficult. If you are doing white-hat SEO with a focus on great content it means you will be rewarded for your efforts.