As things begin building, they come to a point where a small extra effort pushes it over the brink. He uses a series of examples to show how three things come together to create a tipping point, for example: Connectors, Mavens and Salespeople. The Connectors keep in contact with a broad variety of people. They do not necessarily know much nor are they really good at convincing people to do things, but they can connect a people from very different walks of life. The Mavens stockpile information. Where the Connector works to stay in contact with people, the Mavens gather information so they can share it with other people. Salespeople do what the Mavens cannot do, convince people. When things reach the tipping point, these three types of people get together. The Connectors are able to connect a Maven (who knows stuff) with Salespeople (who can convince people to 'buy' the Mavens 'product', whatever it be) and things can take off.
Interesting tidbit: William Dawes rode on the same mission as Paul Revere, but because he was not a good Connector, Dawes was only able to arouse the two individuals he was assigned to where Revere was able to awaken the whole countryside.