Google’s primary goal is to always return the most relevant search results to users. Whether it is in the form of a paid ad or organic listing, that is their primary purpose.
That being said, it takes a lot of “behind the scenes” work to ensure this happens. Google performs various types of- algorithm updates frequently. Some target content, links, local search and even natural language processing (as with Hummingbird) and of course, search engine SPAM. More