I think its based on ecommerce limitations and AdWords logic/tracking. Obviously Udemy cannot rely on pure 'organic' growth (instructors bringing students), so, Udemy would spend $x to get a user into the platform. If that user ends up in your class, Udemy paid for that student, not you, so it wouldn't make sense to reward you at the same level.<p>Furthermore, I do understand the 'winner takes all' mentality of source tracking for retailers and affiliates. Only very, very sophisticated systems can track multi-source/multi touch and even less can do multi attribution on the fly. (e.g. you brought an Udemy student but he/she decided to use your code on someone else's class, then what? who gets what?....ad absurdum) Something in your head such as, 'why don't we all share revenue equally' is really hard to do in practice once you have to pay for growth. Someone pays for a student, or you bring your own, once at Udemy, many scenarios can happen.<p>I do agree that a more graceful way to do this would be to give that preference for a given period of time (e.g. your student, the one you brought in December gets you 90%, but after your class, that student is taking other classes, so someone else should/may get that higher credit.<p>Ultimately, you are right in that more 'competition' to bring new users seems to be the objective of the arrangement, but at least it rewards the right behavior. You want to reward the best teachers (for acquisition and retention purposes) so while it seems 'unfair' compared top the old system, the old system doesn't scale once Udemy starts paying for traffic.<p>I know, sucks, but this one decision seems less motivated by greed than by the struggle of marketing spend attribution and growth