From iFlowReader.com:

Apple has made it completely impossible for anyone but Apple to make a profit selling contemporary ebooks on any iOS device. We cannot survive selling books at a loss and so we are forced to go out of business. We bet everything on Apple and iOS and then Apple killed us by changing the rules in the middle of the game. This is a very sad day for innovation on iOS in this important application category. We are a small company that thought we could build a better product. We think that we did but we are powerless against Apple’s absolute control of the iOS platform.

(This is becoming a theme – see “Don’t Build Your Business On AdSense.)

Monopoly control of a platform, be it an OS or the web itself, is bad for everyone but the monopolist. That’s why it’s so important to keep the web free and open.