This document discusses using SendOutCards as a referral marketing system for real estate agents. It outlines 5 keys to success, including creating relationships, consistent follow up, automating efforts, and differentiating yourself. SendOutCards allows users to easily create and send personalized greeting cards to stay top of mind with clients and prospects. The system includes features like campaigns, reminders, and tracking responses to referrals sent via cards. Examples shown include cards for anniversaries, buyers and sellers, closings, and open houses. The goal is to use cards to celebrate others and build a referral business through ongoing personal connections.