Do recency and like mindedness play a role in that? Does someone you think you know (do we really ever know anyone?) exert more influence over you? What makes you accept authority?
As we go about this conversation of change - for there needs to be change in business (and in individuals) to accommodate for the rise of social - it's clear that the traditional notions of career titles and influence will be put to the test.
Which means that there are also challenges to the notion that the few usual suspects in any environment, including social media circles, need to set the tone for you.
You decide who has influence over you and your thinking.