I'd agree with Electronician.
If you have personalization set up (which is a default option and the majority of people do) and you interact with a website's G+ page, you will likely see them ahead of similar sites when you do searches related to them.
People involved in search engine optimization have done research on the idea that the more your business engages in G+, the more highly your website will rank, and have found a correlation between the two. Google has come out to say that correlation does not equal causation, and the content on your site and other ranking factors are what drives better rankings. No one really knows for sure the degree to which social media influences Google search engine rankings - except maybe for Google. :)
If social media has a significant influence in search engine rankings, G+ would certainly be the social media platform that Google would weigh more heavily than others.