The Boston Globe has published an interesting editorial piece on the balance theory both in social networks and in the movies.

Balance Theory:

Examples of unstable social network include Mexican standoff in “The Good, the Bad, and the Ugly” and “Reservoir Dogs” with all three pointing guns at each other.

On the other hand, if you and someone else hate the same third person, but like each other, balance theory says you’re golden - all three can persist without changing their opinions.

Six Degrees of Separation:

Back in the 1960s, the psychologist Stanley Milgram attempted to measure the number of connections separating people in Nebraska and Kansas from those around Boston, and found a typical distance of about six steps. Since then, this concept of a tightly connected world has captured the public imagination, and in math and science has spawned a large field known as social network theory.