Collaborative filtering usually involved the process of rating previous content
and showing the ratings to user so that they know the collective opinion
of a piece of information without having to read the information themselves. This allows a person to focus on the good information while avoiding the bad.
Recommendation: Everything2 should allow you to know the rating of nodes
before you jump to them thus you do not have to encounter low traffic and low quality nodes
of you only want to popular good stuff.
Also there are two types of collaborative filtering: implicit collaborative filtering
and explicit colloborative filtering