Weak Ties, Strong Ties, and never wear striped ties with striped shirts:

Malcolm Gladwell compares the Internet age with the Civil Rights movement and argues that true revolutionary change occurs through face-to-face contact not Facebook contacts. While weak ties, Gladwell argues, help generate new ideas, strong ties generate resolve. "A networked, weak-tie world is good at things like helping Wall Streeters get phones back from teen-age girls," Gladwell concludes after relating a story in which a lost/stolen cell phone is recovered. However, if you want a true revolutionary movement to take place, you need a hierarchical structure, preferably lead by a charismatic leader like Martin Luther King, Jr.

On the other hand, generating new ideas, being creative, works better when the emotional ties between people are not particularly strong. We don't like to be challenged by those about whom we have strong feelings. We want to be reassured by them. Think how disturbing it is to have to admit that someone you hate actually has a good idea. Or to be shown inadequate or wrong by someone you love.