One critical tipping point that I've observed (as a developer) is the difference between $.99 and Free. Early in the app store Apple decided they you could onl

One critical tipping point that I've observed (as a developer) is the difference between $.99 and Free. Early in the app store Apple decided they you could only leave feedback for apps that you actually installed. From that point on, you had to download the app to rate/review it and if it was a paid app, you had to pay for the privilege. This seemed to filter out allot of the off-the-cuff negative comments for paid apps; maybe because it raised the "bozo threshold" or maybe because when you pay for something, you try harder to get something out of it. Either way, negative reviews for paid apps dropped for me (and seemed to across the board). I'm experimenting with this again by making one of my paid apps free for a week, we'll see what the score looks like after that.