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.
An affiliate agreement is when a company or an individual agrees to pay you for successful referrals. For example, Amazon has a massive affiliates program where they pay you a percentage of the sales you generate using their affiliate links. Affiliate marketing is everywhere these days. In fact, we’re able to offer our own Blogging Mentorship Program for free because Bluehost sends us money for every customer we refer.