I don't think that Google will go in this direction.. Just because your website is +1’d or shared on Google+ does not mean it will be favored over other websites. But maybe later, Google plus and Google are connected so why not..
I guess google+ doesn't have that much effect this early since it's just starting, likewise on facebook it eventually becomes a way of boosting a site's popularity. So i guess google+ will be going in that same direction eventually.
Google + is going to be the best solution for the SMO as the user's are increasing day by day in the Google +. And the second most important thing is that Google is behind this.. all the SMO , SMM and SEO is behind the Google.
Exactly at 08:45 minutes Matt cutts answered as They are working on it. If some website is blocked by many number of users it will have a negative impact. We can conclude the other side by ourselves that, if it has pluse by many it will have a positive impact by default.