A number of developers offer free or "lite" versions of their apps to entice would-be customers to buy the full version of their software. But that's a business decision by the developers, not App Store policy.

Posner has a novel suggestion: "Since the iPhone and App Store comprise a closed platform, it shouldn't be too hard to build in an effective self-destruct feature for applications after the preview period expires."

Name games

Many apps have similar names, so it's sometimes a challenge for customers to tell what they're getting. The App Store offers several different unit conversion apps, for example, all with variations on the same name--Units, Units Convertor, Converter by UnitConvertr, and Converter by Architechies, to name a few.

Similarity in names often means similarity in function. "There are a lot of apps that do exactly the same thing," complains Arnn. "And most of them seem unnecessary." Arnn says being able to easily compare and contrast similar applications would be a helpful feature in the store.