While there was that and an occasional WebKit security exploit that needed patching, those were the security exceptions that proved the need for tight sandboxing requirements. Clamping down on what data apps could access from the get-go ensured that iOS would remain to security threats Android.

Clamping down on the data that Mac App Store apps can access empowers Apple to assure its customers that the third-party software they install is safe and won't compromise their Macs. And Apple certainly wants to reassure its users that Macs are supremely safe, especially after the disappointing blemish left by the . If Apple sees its alternative as waiting for the day a rogue Mac App Store title maliciously starts abusing user data, the sandboxing requirement seems like a no-brainer.

Apple hopes--and likely expects--that Mac App Store customers won't notice anything has changed as they start installing sandboxed apps from the store. For many niche or narrowly-focused apps that don't need access to any extras (think games, todo list managers, and the like), that should indeed be the case; sandboxing those apps shouldn't have any tangible impact on the user experience.

But in other cases, developers may be forced to sacrifice features large and small to comply with Apple's security requirements. 's popular image editor Acorn, for example, offers a clever shortcut for power users: When saving an image, merely changing the filename's extension automatically tells the app to adjust what format you're saving the file in. The sandboxed Mac App Store version of the app won't support that feature, Flying Meat's Gus Mueller told , because--he believes--of under-the-hood changes related to how Save dialog boxes work within the sandbox. Mueller stressed that he's not certain precisely why the feature doesn't work in the sandboxed version of Acorn, but he's been devoting his time to figuring out other, more pressing sandboxing issues, like .