In these days Search Engine Optimisation is not restricted to the On page and Off page factors only. Instead, many social influences, likes and dislikes, downloads, bookmarks are really making the ranking job tough for SEOs as a whole. Social media discussions and participations are really important factors to include depending on which the search engines would put values to those brands and pull them up in the SERPs.
In the above diagram I have tried to depict the entire scenario in a brief. The picture also shows why we need the social media involvement and the actual purposes.
Review Sites: These sort of sites are working a word of mouth and written reviews help the users to choose the choice-able product and services. Negative reviews take toll to the name of the brands and thus the ranking factors. We had an experience on this. So customer service is gonna really matter these days and Twitter comes handy for this. (So relationship pattern)
User Engagements: Once we try to engage the users or the visitors around the brand, they will suggest us what to do next. This is somewhat wisdom of crowd and they will in fact drive the sales growth and revenues. The likes would also send a signal to the search engine that how the brand is performing.
Google+: This is really effective for the business. More the plus, more faster will be the rankings via shares and engagements. This is actually Googles own product and so quite obvious that google will put importance to its own product first.
Downloads and Views: This is another component via which the search engines got yo know the visitors preference. The bottomline line is that, what visitors prefer, Google will prefer the same. The value of the contents are really crucial. More research, new stories, data driven content and associated users views, likes and downloads are the key determinants for the overall SEO rankings.
It goes without saying that the importance of analytics is of course to be taken into account to fix the bounce rate, usability structure, exit pattern, and lot more.