I've thought about that, however I worry about it turning into what Facebook does and put you in an echo chamber (with the occasional "across the isle" item thrown in to "make you angry"). But I still like the idea, just not sure what the best implementation would be.

Some ideas I've had include having multiple up/down vote buttons for different criteria -- one that says if you agree or not with the content, and another one that says if it is a well reasoned and interesting post. That way I can pull up things that people in my cohort think is a good post but also disagree with content wise. But this requires that people are reliable able to judge something fairly that goes against their view.

Then I'd like to see "bubbles" that show which cohort(s) I belong to and which other ones are out there so I can choose which to read at any one time.