An experiment showed that two random people are likely only separated by ~6 people, largely thanks to certain individuals who connect broad swaths of people.
There was an experiment in which a series of dozens of letters were given to random people with instructions to write their names down, then send the letters to whoever they thought could best get the letter to a certain individual across the country. The instructions were to repeat this process until the individual at the end of the line got the letter. Most letters made it across the country with 5 to 6 steps. That means, in this case, we found that randomly connected people were connected usually in 7 or fewer steps.
We found though, that typically there are a few key people with extra wide social networks. These people are connectors that have broad networks that connect each other. These connectors enable broad “epidemics” look of social change. Paul Revere was a connector. These 20% of the people, do 80% of the connection (figuratively speaking).