There is a fundamental conflict of interests in asking for new information from a diverse cross section of people (aka the web) while also wanting to only see those things with which you already agree.
If your purpose is knowledge or worldly depth/breadth, there is probably greater value in doing exactly the opposite. You know best those things which you already like.. so exposure to those ideas you don't already like would provide the greatest bang for the cognitive buck.
But reddit, digg, and HN are all sources of group-think, not really diversity.
Of the 3, HN is the only one that really welcome true contrariness SOMETIMES, but I've still been downmodded for pointing out biases and groupthink here.
They always crucify the heretics. It's an group instinct that thwarts leadership and completely counter to the theoretical intention of HN. This should be a tribe of heretics.
If your purpose is knowledge or worldly depth/breadth, there is probably greater value in doing exactly the opposite. You know best those things which you already like.. so exposure to those ideas you don't already like would provide the greatest bang for the cognitive buck.
If anything, we need less filters. (imo)