Abstract: An advertising referral service operates a referral service website including a listing agent interface that allows a listing agent to offer ads for placing on websites and a hosting agent interface that allows a hosting agent to select an ad offered by the listing agent and place the selected ad on the hosting agent's website. When a visitor to the hosting agent's website activates the listing agent's ad, the referral service records a credit entry to the hosting agent and a debit entry to the listing agent. The referral service reports the credit and debit entries to the hosting agent and to the listing agent.