Big up to Gareth for spotting this piece by Sociologist Prof Duncan Watts of Columbia (that's him on the left, I believe) challenging (or skewering, maybe?) the simple 'influence' models that lie behind many of the Buzz-marketing businesses which have sprung up in recent years...
I've long thought that the Buzzmaniacs are wrong. There isn't just one group who does all the influencing, across all categories. Personally, I much prefer the work that Stephen Phillips and Fiona Blades at Spring Research did in their landmark MRS paper Decisionwatch UK.
In the (now infamous) case of Alison's new Mercedes, they tracked back all of the different types influence and influence on Alison which together resulted in a contented Ford Fiesta Owner becoming - in just 2 weeks - a rather surprised Mercedes A series owner. Stephen and Fiona traced at least 8 types of influencer and - now having applied it to a number of other categories - believe that not only can one individual play different influence roles in the same purchase but that different types of purchase have different types of influencer involved...much more complicated, you see.
As far as I understand it, Prof Watts' work is based on simulating different influence models which all goes to show that it's just not that straight forward.
My old chum Mark Oldridge and I used to joke over the illusion that "leading edge" consumers had any influence in tech markets, "they're too busy playing with themselves and their handsets" was our ribald conclusion.