Here's the explanation from the horse's mouth. (http://www.livejournal.com/users/_imran_/20116.html?thread=52116#t52116) Basically, there is a list of interests that are most popular that livejournal keeps. The congruence of your friends' interests list with that list determines the normality.
no subject
Date: 2005-08-11 10:52 pm (UTC)