good image dayum. anyway social signal =/= social signal.
lets say social signals divide for links and for url likes
if people were linking our page on their walls on facebook naturally it wouldnt change anything. Wall of facebook profile isnt crawlable (its private). but anyway even if it was crawlable = most of the time it wont index on it own, so we can have big social pages on any social platform but most of natural links wont index anyway.
other thing is when someone +1 or likes a URL = im not sure how google checks that and how url stats are getting indexed but I also didnt see any change while having some signals like these.
To me links from sites such as Facebook (even nofollow) are authority links. I get them anyway (if I can), from as many places as I can (social,parasite,anything with big successful site that offers you a backlink)
theres also such thing as authorrank - or maybe its not existent, but brand awareness starts from official facebook,G+,twitter,linkedin pages.