Apple (Nasdaq: AAPL) has pulled one of the more popular third-party offerings from its App Store, after developer tap tap tap revealed a secret feature on its Camera+ program that runs afoul of Apple's rules.

MobileCrunch and several other Apple-centric blogs are reporting that Apple nixed the $1.99 photo-shooting enhancer after the developer sent Twitter followers instructions on unlocking an Easter egg in the program, which allows shutterbugs to use the device's volume keys to snap a photo.

Brilliant feature, right? One of the iPhone's awkward shortcomings -- beyond the latest model's antenna troubles -- is the need to snap a digital photo by using the touchscreen viewfinder itself. Having physical controls on the side is more conventional.

Unfortunately, Apple doesn't see it that way. Developers aren't allowed to tweak those controls, and tap tap tap has to know that. Why else would it slyly reveal the feature, instead of bragging about it in the App Store description?

Earlier this week, tap tap tap revealed in its own blog that it racked up sales of $507,221 of Camera+ during its first two months on the market. That's a lot of money being made in a competitive storefront, especially amid countless free ad-supported alternatives.

Something's got to give at this point. Apple is too big and popular to cave in to circumventing developers, but it has to respect that it would not be where it is today without third-party tinkerers.

Google's (Nasdaq: GOOG) collective of Android phones outsold Apple during the first quarter of the year. Research In Motion (Nasdaq: RIMM) still has more BlackBerry devices on the market. Nokia (NYSE: NOK) remains the global handset leader. Microsoft's (Nasdaq: MSFT) Windows Phone 7 is late to the party, but don't underestimate the software giant's resources if Mr. Softy decides to catch up in a hurry.

Right now, the App Store is the marketplace of choice for most mobile developers, but Android's open-source nature is catching on. Everyone else may be off in the distance, but they won't always stay there.

Apple has routinely come under fire for the programs it rejects -- or occasionally, the ones that get through. However, pulling an app that Apple itself has featured is a risky move. If Apple's user base decides that it wants an iPhone's volume buttons to be more than volume buttons, it can't be good business to rain on that parade. Isn't "the customer's always right" the reason why Apple is handing out free bumpers to iPhone 4 owners?

Surely, the developer can't always be wrong. Rules are important, but following them too ruthlessly may become the undoing of Apple's App Store.

Is Apple too strict with its App Store rules? Share your thoughts in the comment box below.