There’s an interesting story developing on the App Store front today. It seems that Apple has just pulled the popular Airfoil Speakers Touch application from its digital download hub, without offering up any kind of explanation.

If you haven’t heard of the app before, it’s essentially a utility that allows allowed you to stream audio from your desktop Mac or PC to an iOS device using AirPlay. It’s been in the App Store for years. So why’d Apple pull it?

Here’s what Rogue Amoeba, the developers of the app, had to say about the matter:

“Today, we’ve been informed that Apple has removed Airfoil Speakers Touch from the iOS App Store. We first heard from Apple about this decision two days ago, and we’ve been discussing the pending removal with them since then. However, we still do not yet have a clear answer on why Apple has chosen to remove Airfoil Speakers Touch. Needless to say, we’re quite disappointed with their decision, and we’re working hard to once again make the application available for you, our users.

As far as we can tell, Airfoil Speakers Touch is in full compliance with Apple’s posted rules and developer agreements. We’ve already filed an appeal with Apple’s App Review Board, and we’re awaiting further information. Unfortunately, Apple has full control of application distribution on iOS, leaving us with no other recourse here.”

Apple has long-since been criticized for its “walled garden” approach to its iOS platform. It’s even notorious for rejecting and removing applications from the App Store without much word or warning. But this is different.

Most apps that manage to slip through the App Store’s tedious approval process are generally pulled within a day or two if Apple sees fit. So how did Airfoil Speakers Touch manage to survive for nearly three years?

Cult of Mac has an intriguing theory behind Apple’s actions. The site says that it has learned that the app duplicates an upcoming iOS 6 feature:

“According to our tipster, Airfoil Speakers Touch wasn’t yanked arbitrarily, but instead because it duplicates functionality in the still unreleased and officially unannounced iOS 6. Our source says that in iOS 6, an Apple TV, for example, can pipe sound from a movie to an iPod touch, iPhone or iPad, and any iOS device will be able to beam audio to another. We’re trying to get more details, and have reached out to Apple and Rogue Amoeba for comment.”

An appealing concept for sure. But why would Apple pull the app 6 months before iOS 6 is expected to go public? And how would it explain this to other developers? “Sorry guys, if we like what your app does, we’re going to build it into iOS and ban yours from the App Store.”

A more likely scenario is that a security issue has been discovered in the way Airfoil Speakers Touch interacts with Apple’s products. Or perhaps the software conflicts with a new addition or feature in iOS 6, and it just needs to be corrected. There are dozens of possible explanations.

Still, it’ll be interesting to see how this whole story plays out. And we’ll be sure to let you know as soon as more information becomes available.

Why do you think Apple pulled the app?