"What's wrong with earning a few dollars providing a useful service?"
Nothing. It's when you have also have a service that promotes the sharing of other people's commercial work for free (and say it's because you thing that sharing is for the good of the world). It's hypocritical and the people in this forum don't seem to see a problem with it.
I suppose I will just go with the flow and pirate any user's app I see on here.
(pirate bay founders create flattr)
http://techcrunch.com/2010/08/12/pirate-bay-founders-flattr-...
Here is the video where he talks about sharing:
http://www.youtube.com/watch?v=IyGCsCpofVk
"How do you know they are profitable?"
Bandwidth isn't that expensive. With all of the micropayments that will go through their service, they will make a profit.