My Secret Purposes Are Secret On Purpose

Facebook needs some manner of collaboratively-generated "context" reference for those friends who bulk up your count but do very little else in the way of enhancing your Facebook for the simple reason that the details of your shared past is limited only to the count of intersecting friends.  Perhaps such a reference tool could be disguised as one of those Likeness-esque applications that are constantly nagging for my personal assurance that I am, indeed, a person with 80% knowledge of "Buffy: the Vampire Slayer" character likes and dislikes.

I imagine it would work something like this: I would select a target person(s) about whom I want to know more (specifically: "How in the hell do they know me?" and "How should I know them?") and then a smartly designed, dynamically-generated quiz would be sent to them disguised as a challenge to match my score. If they were sucker enough to accept the challenge they would find a brief series of random questions, of which half would be designed to help me narrow the possible ways I might know them (e.g., "What's you best memory about Aaron"; "Is your illegitimate child a ginger?"). Upon completion, the application would return their answers to me while assigning them a totally innocuous and largely irrelevant rank/badge of accomplishment (e.g., "You scored a 75/100.").

Or, I suppose I could just be a bit more rigorous in who I accept on FB, but that seems like too much work.