If the average distance on the social graph between any two people is on the other of 6, 8 or even something larger like 20, is social graph distance a good pre

If the average distance on the social graph between any two people is on the other of 6, 8 or even something larger like 20, is social graph distance a good predictor? Additionally, the prediction quality is lessened when people are not very discriminating in who they link up with, or all edges on the graph have the same weight or can not be tagged with useful, meaningful metadata. Who's going to spend the time to provide that metadata anyway? Wasn't there some research a while ago that showed that six-degrees of separation is more true than is intuitively not?