Well, the effect doesn't preclude the possibility that there are connections you specifically want to avoid. My point was just that the value of the social network is the connections - Facebook would be even less useful if none of your friends were on it in the first place. Managing who sees what in a way that jives with social dynamics is still something these networks are figuring out. Charging $50 is far more likely, however, to keep out my unemployed friends than my well employed parents.