For a while now, Google have been basing a lot of the search results you receive on what your social links have been sharing, talking about and rating.
To see how influential your own social graph is to your Google Search results, try this search query:
It's just a Google search for macmillan, but the tbs=frim:1 bit at the end makes any Google search query only use your social influences.
You'll see why you receive certain results by the line under each one saying things like:
Katie Smith shared this Macmillan Cancer shared this on Twitter - 28 Jun 2011 Mike Hobday shared this on Twitter - 4 Oct 2010 Macmillan - Digital shared this
Rebecca Cryan shared this on Twitter - 4 Feb 2011
Since each Google Search for the same term can now return completely different results for each user, influencing the usual dumb search is becoming less and less important. Queries like the one above, along with the work of Louise and Richard in Marketing, help us understand how our social interactions are influencing our search rankings... and for whom.
There's more on this SlideShare presentation.