---- Social signals don't seem to be very important, yet.
anallawalla - 3:16 am on Dec 10, 2012 (gmt 0)
In fact the top ranked pages don't even have social profiles
Google might use social signals as a tie-breaker somewhere in the domain trust part of the algorithm. It might use it to add to an AuthorRank score, which won't apply to many business sites where there are no identifiable authors. I don't believe that every ranking situation requires the presence of social signals - in fact, if I were designing the algo, I might not use social signals at all in many niches.
But niches that use a lot of social media, such as celebrity content, can benefit from social signals.