commit: fb200d8 - #595 (2014-04-14 00:44:57 -0400)
I think this article covers well that at the same time as the number of 'linkers' might be reducing the quality of manually curated links should be more accurate (in theory) than quick 'traffic light clicks' on a like button which somewhat devalues 'social links' and 'real world shares' as a mark of value. http://searchengineland.com/where-have-all-the-linkers-gone-158962 I can see links becoming less important, but personally can't see them being totally devalued and replaced with any one measure be it social or otherwise. http://www.stevebrownlie.com/2013/author-rank-will-not-replace-links/
The Knowledge Graph will step by step replace search resulsts, just look at Conevrsational Ssearch and Search on Google Glass. So the future of SEO will be: no more traffic from Google as searchers will stay on Google itself and just read your stolen content there.