Moz published a story yesterday showing a high correlation between Google +1s and Google's search rankings.
Shortly after, Google's head of search spam, Matt Cutts, went over to Hacker News and debunked it. He said, +1s do not have any impact on search rankings at Google.
Just trying to decide the politest way to debunk the idea that more Google +1s lead to higher Google web rankings. Let's start with correlation != causation: http://xkcd.com/552/
He then went on to add:
If you make compelling content, people will link to it, like it, share it on Facebook, +1 it, etc. But that doesn't mean that Google is using those signals in our ranking.
Rather than chasing +1s of content, your time is much better spent making great content.
Yep, that does make sense. But do you believe him? Many in the industry do not. So Matt Cutts had to respond to more people in the thread. He added:
Suffice it to say that I would be very skeptical of anyone who claimed that more +1s led to a higher search ranking in Google's web results.
Most of the initial discussion on this thread seemed to take from the blog post the idea that more Google +1s led to higher web ranking. I wanted to preemptively tackle that perception.
Truth is, Google is to blame for the confusion. In August 2011, Wired published a story suggesting Google+ was tied to ranking. Google's chairman suggested it as well in February 2013. Matt Cutts did say at conference it is not used but did say that authorship is a good signal, which can be confusing for users.
Anyway, I do believe Matt when he says +1s are not used directly in the ranking algorithm.