It is Google who circulates your web page over Google search engine. And it is obvious that their own product will definitely help you in ranking on SERP. Your Google+ page allows customers to find your webpage on various Google platforms, including Maps and Search. You can say that you are getting all the advertisement for free. Google+ Hangouts is another awesome thing Google+ has to offer. The main benefits of Google+ on search results is seen in various surveys. If you keep being active and engaging in Google+ then it increases your visibility on Google+ and all other platforms.
You can leverage Google Plus by basic three ways - drive more traffic to your web page, marketing via making relationships with fans and followers, authorship with your picture beside your article. These things will help you in Google+ marketing. Here is an infographic which explains all the possible ways to leverage it.
Source : QuickSprout