ZydoSEO - 3:00 am on Sep 16, 2012 (gmt 0)
I agree with many here that social signals are just as manipulative as if not more manipulative than links. Cutts said recently essentially that links will continue to weigh heavily in their ranking algorithms. There is a reason for this.
Even though there is a lot of web spam in the name of building artificial/unnatural/non-editorial links to web sites, at least Google and other engines have been dealing with it for a LONG time. They know what it is. They know how to recognize it really well manually, and are even getting much better at doing so algorithmically (Panda/Penguin). And the engines have processes (spam reports, Google Quality Raters, Googlers performing manual reviews of sites) and systems/infrastructure in place to deal with it.
Rewind to 10 years or more ago. That is where the engines are with Social Media. They don't really know how to deal with it. Hell they can't really get to any useful data other than their own (G+ in Google's case). Even if they "could" get to all of the Open Graph data at FB and all of the Tweets at Twitter, they would not know how to recognize fake accounts any more than Twitter, FB, LinkedIn know how to recognize it. They have no processes and systems in place for dealing with it even if they could recognize it.
And trust me MUCH of social is VERY fake. As moderator for Search Engine Lands LinkedIn group, I see hundreds of new fake account every day. All of the major social networks are rampant with fake accounts. And regardless of what they say, even the networks themselves are capable of doing anything about it. They want you to "think" they are/can police it. But the networks are spammers' playgrounds.
If you were a search engine, which would you choose? Dealing with a known evil (links) that you know and understand and have a decade of experience identifying and dealing with? Or dealing with a new evil that you can't even see/identify and have virtually zero experience dealing with?
IMO links will continue to be important at all of the major engines for a very long time. While I do view social as a means for building brand and driving some targeted traffic if done correctly, I don't see the engines really making any significant headway in using social signals as significant ranking factors anytime in the near future.