wheel - 5:05 pm on Dec 12, 2012 (gmt 0)
And just an FYI. I have a reasonable social media presence, entirely as the result of other marketing that I do - I get tweets and stuff. And if we remove the ranking boost (which I believe doesn't exist in any measurable fashion) then we get to this:
One thing is for sure - social media helps to spread high quality content both on the website and off, which can lead to better performance.
And my experience has been that for me, it drives exactly 0 business. In fact all my non-google pushes drive almost 0 business. My mainstream media mentions in national daily newspapers, radio interviews, book sales, all drive almost 0 new business. I do it for other reasons, if I was measuring $ return, I wouldn't be doing it. People think that a mention in a national paper is going to drive sales. It doesn't.
I'm suspicious that there may be another ranking factor that Google's using to muddy the waters, but I don't believe it's social media. It may be some trait that they're using to measure 'brands', or type in traffic, or some wierd quality of links. There's stuff that's ranking that I don't know why they're ranking - but it's not social signals IMO.