Apple doesn't like apps that require you to register for an account before they'll work. One such app was reportedly rejected is "Read It Later," which needs a user account for you to save articles. Apple's rejection notice implied that Read It Later shouldn't be requiring customer registration, because it doesn't provide any "account-based features." Bullpucky! Here's what Apple said: "Applications cannot require user registration prior to allowing access to app features and content; such user registration must be optional and tied to account-based functionality."
Here's the full email: