The modders have much work to make the best possible their projects. It was interesting to create something that can reward work while protecting a little. The mine idea was something like the Apple Appstore but for the contents of the rFactor2. Certainty that the quality was improved knowing that his work was rewarded. It's a crazy idea to some, but also said the same of steve jobs.
The aspect of payment-as-reward was touched on here: http://isiforums.net/f/showthread.php/1245-What-would-you-pay-for-a-great-mod
