You invite friend B , and B register as a member and complete first review task. Then you get $3 for registeration commission. When B invite friend C ,and C register as a member and complete first review task. Then you get $1 for registeration commission.

For example : Invite 10 person earn $30,
100 person earn $300,1000person earn $3000;
even more ,because Your friends will invite their friends,
and you still earn $1 from it.

Example:
You invite friend B,and B register as a member and you get 6% for every B complete task.

When B invite friend C, and C register as a member and you get 4% for every C complete task.