Just imagine...

Imagine walking into a large room filled with people clothed in colors indicating the number of things they have in common with you: white indicating nothing in common, light green meaning one thing, orange for two things, etc., on up to, say, purple indicating that you have twenty or more things in common with that individual.

Now imagine everyone grouped by clothing color, those in white off to your right, those wearing light green to their right, etc. By simply looking at anyone in one of these groups you would know exactly what the two of you have in common. These could be things like your age range, hometown, hobbies, sports interests,education...or even things that you don't normally reveal publicly, such as phobias or addictions, but with whom you'd gladly admit to someone you share them with.