I am not sure i understand correctly. How would donors end up paying twice when its a for-profit venture. In the equity model you get a small equity or a right to sell something. Say for example, if you are developing an app to be sold on Apple iStores. Now when you crowdfund the development of app then you probably get the revenue rights from say installs starting from 1000 to 2000. This is a very innovative mechanism of funding. However, there is another dark side to this. Crowdfunding is becoming a tool for money launderers.