It seems there's a lot we don't yet understand about social networks. Contrary to Granovetter's "Strength of Weak Ties" (pdf), we are beginning to discover that strong connections may be more important for social change.
Makes sense. Situational awareness (e.g., job opportunities) can be expanded by communicating with folks further from the center of our flocks. But when we have more to risk - striving for real change, requiring sustained commitment and significant self-sacrifice - mutual trust becomes more important.
It seems that to be informed and effective, we need to cultivate both weak and strong relationships.