When there are multiple affiliates involved in one transaction, payment gets much more complicated. Sometimes it’s even possible for affiliates to jump in at the last minute and claim commissions for customers brought in by other affiliates. Successful programs use multi-channel attribution to ensure the affiliates that create the most value get paid the most.
Affiliate marketing is also called "performance marketing", in reference to how sales employees are typically being compensated. Such employees are typically paid a commission for each sale they close, and sometimes are paid performance incentives for exceeding objectives. Affiliates are not employed by the advertiser whose products or services they promote, but the compensation models applied to affiliate marketing are very similar to the ones used for people in the advertisers' internal sales department.