Google is now integrating its social network data within the search result, to build a more personal search engine result. I bet this will change the whole SEO business model. Read more here: http://edition.cnn.com/2012/01/10/tech/web/google-search-plus/index.html?hpt=hp_bn6
Google it's getting too "complicated". In the start, they had success because they were very simple comparing to Yahoo and others at that time.
I have just been reading about this myself. A very bullish move if you ask me, so if i understand this right, if a post has been shared by someone in your google plus social circle, this will rank higher than other results? lol