Agent-to-Agent Referrals

I am getting information together for a class on agent to agent refferals and would love to know how many of you use this untapped resource. Statistics in 2006 state that only 8% of buyers and sellers found an agent through another agent or broker. Are we looking out for each other? Thank you and I would love to hear your comments on the "pros" and 'con' of agent referrals.