I'm going to start off this post by stating that I have not tested this theory, and I can in no way prove it. The following is a very strong belief I have based on intuition.

I believe that Social Media can dramatically increase organic ranking aside from link popularity. Google uses analytics, their toolbar, and other proprietary methods to track information about website traffic. Let's say that Google wanted to track the size of a company or organization and its advertising budget in the physical world. One of the most obvious and proven methods that Google uses to track some of this information is link popularity. 

What's the next logical step in this process? If you develop a popular product or service, have a large marketing budget and create powerful brand recognition; then, you should have a large amount of direct 'type in the url' traffic and returning visitors. Analytics and other popular traffic statistics programs have tracked these metrics for a while now.  It's my belief that Google will rank your website more favorably over time if you have more returning visitors and direct 'type in the url' traffic. One of the most powerfully optimized and successful sites I've ever created has a ratio of new visitors to returning visitors of 50/50. This site completely dominates an entire competitive market on Google. I do understand that one possibly special cause in variation cannot prove or suggest much of anything. Social Media, an interactive and updated website, valuable content, and traditional marketing can improve these statistics. Does anyone else have an opinion on this topic?

"The minute you think you're over-thinking what Google may potentially do, or be capable of doing, you've lost the game."