A vanity URL is a unique and custom URL that is created specifically for a program participant to share with their contacts. The URL is usually shorter and more memorable than the standard referral program URL and often contains the participant's name or a specific identifier. When the participant shares this vanity URL with their friends, family, or colleagues, it directs them to a landing page where they can learn more about the referral program and sign up. This helps to track the performance of the participant's referral efforts and rewards them for successful referrals.