viral - 5:51 am on Jul 17, 2013 (gmt 0)
I personally think one of the "brand signals" Google is looking at is the number of times someone searches for your url.
Say you sell "blue widgets" and your site is called bluewidgetdepot.pumpkin or whatever tld you want. If people aren't searching for "bluewidgetdepot" or "bluewidgetdepot.pumpkin" then Google is going to find it hard to justify ranking you for "cheap blue widgets", "blue widgets" or "best blue widgets" or whatever.
This is where social comes in to play. It gives people a sniff of you and your site before Google has even started ranking you. With a lot of social chatter going on around your site, people may actually start searching for your url/domain name. Google will then find it hard to ignore you.
As an aside I think this is part of the reason that some exact match domains are still good. Because if you get the right kind of domain you already have people searching for you. Of course this EMD has to be backed up with content, links and relevancy but I still think done right a good EMD will out perform a PMD or a new companies branded only domain.