I agree that if he's putting in work and helping people she's eligible for some form of compensation!
However I think as a community it'd be sweet if we could come up with a range of percentile that we figure is "fair" so that in the future people whom are looking to get featured are the ones benifiting the most from their work.
The difference is that @stellabelle talks to them up front. They agree to her terms. That makes it fair. What people do on a contract and agree to is not for you or I to determine fairness. That is between the people the contract involves. If they are fine with her taking what she does, then so be it.
I can tell you if I wrote something and gave it to @stellabelle that 30% would likely be my biggest payday to date. I'd be ecstatic!!