A thought exercise.
At one end of a spectrum we have the classic webfeed aggregator. You tell it where to look, and it brings back a bunch of stuff. Whatever it finds, you get. The aggregator never changes where it looks.
At the other end of the spectrum, you have Findory. You don't tell it anything, explicitly, and it brings back a bunch of stuff. Depending on the profile of you that's built, you get different stuff from different places.
What would an aggregator somewhere in the middle look like?