A two-tier program is an affiliate marketing program in which an affiliate gets paid for sales or traffic that merchants get directly from the affiliate sales or traffic from another affiliate that joined the program through the recommendation of the first affiliate.
The first tier in this program is usually similar to the regular affiliate marketing program. The major difference is the additional tiers from which the marketer gets extra commission from the sales that the affiliate under them makes. With this structure, the affiliate receives some commissions, not for their work alone but also for another affiliate that joined through them.
These compensations are sometimes written in shorthand like tier1/tier2.
As an affiliate in a program like this, it’s crucial to pay attention to fine details, especially for second-tier compensation. You must determine if the commission is a straight percentage (such as % of the revenue that B generates) or a percentage of percentage (such as % of earnings that B generates).
Realistically, affiliate programs can have an indefinite number of tiers. However, there should be practical limitations, such as the two-tier model. Otherwise, these programs may attract affiliates that wouldn’t do anything but profit from other people’s work.