This is very common in the App Store. Apps that decide to go free after charging typically take a full one-star downgrade to their rating.
Lots of people download them because they are free and don't care that much about them and are uber-quick to think they are terrible and move on to the next free app. Whereas people who pay are much more interested in what it has to offer, give it more time before they move on etc.
App.net is probably experiencing some of this with their backers. If it were free it would likely have much worse 'reviews' from people. Not that there is anything wrong with the product, just that people who spent $50 are much more likely to give it more than a quick once-over before making up their minds about it.
The App.net effect is due to sample bias -- the people paying are the one's most likely to be enthusiastic about it, so they are enthusiastic about it to justify the fact that they spent $50 for it. They don't want to feel like they've wasted their money. With App.net, users have a vested interest in other users adopting the service, hence the cheerleading.
Lots of people download them because they are free and don't care that much about them and are uber-quick to think they are terrible and move on to the next free app. Whereas people who pay are much more interested in what it has to offer, give it more time before they move on etc.
App.net is probably experiencing some of this with their backers. If it were free it would likely have much worse 'reviews' from people. Not that there is anything wrong with the product, just that people who spent $50 are much more likely to give it more than a quick once-over before making up their minds about it.