I don't really use Facebook that much, but a few months ago when I started using it, when you clicked on a person's friends, you could see how that person and their friend knew each other (i.e., went to college together, etc). Now when you view a person's friend list, that information is not there. Did I change a setting, or did Facebook change privacy settings or something?
Facebook have tweaked the friends listings recently, and it looks like that information is no longer viewable for some reason.