I would argue that edge rank reinforce personal and group biases and let you see more of what you interacted with.
Believes (false or true) start with an event that leaves an imprint in you and later you start "seeing" only what goes along you believe and minimizing or ignoring what is against your believes.
So if edge rank would feed you more of what you interacted with your view would become more and more extreme.
If edge rank is aware of your context and your social graph, it will also feed you more and more what your social circle consumes and produces.
We can see what is going on in the whole world but we are still made by our local reality.
Believes (false or true) start with an event that leaves an imprint in you and later you start "seeing" only what goes along you believe and minimizing or ignoring what is against your believes.
So if edge rank would feed you more of what you interacted with your view would become more and more extreme.
If edge rank is aware of your context and your social graph, it will also feed you more and more what your social circle consumes and produces.
We can see what is going on in the whole world but we are still made by our local reality.