When you talk to people who are seeing a church planting movement, they all talk about the importance of people passing on what they are learning.
Neil Cole says in a recent blog post at http://bit.ly/asqEgw that every church he has started has begun because people become Christians going through the 7 signs of John. One of the questions that is asked in this evangelistic Bible study is "Who do you know who needs to hear this?"
David Watson has seen tens of thousands of churches start in many different countries of the world. In this country, he uses Bible study as the way to start them, and again one of the questions asked is "Who do you know who needs to hear what you have just learned?"
Curtis Sergeant who saw a church planting movement in China talks about the importance of discipleship chains–whenever someone learns something, they are responsible to pass it on to at least two other people, who in turn pass it on to two more.
The next time they get together, there is accountability. "Did you pass on what you learned to the people you mentioned who need to hear this?"
If new believers (or even unbelievers) are encouraged to pass on what they are learning to others who don't yet know the Lord, the Kingdom will spread quickly.