An affiliate refers customers to an operator through a website, app, social channel, stream, email list or paid media, and is paid under an agreed commercial model such as CPA, revenue share or a hybrid deal.
Affiliates range from one-person content sites to large media groups. Streamers and content creators who promote gambling brands for a commission are affiliates too.
In regulated markets the operator is usually responsible for what its affiliates do on its behalf, which is why operators vet affiliates before approving them.