Three months after the public launch of iCloud, I thought it’d be interesting to check upon the App Store and see how many developers have decided to enable iCloud integration for documents & data storage in their apps.

iCloud went live alongside iOS 5 and OS X 10.7.2 on October 12th, two days ahead of the iPhone 4S’ launch. In retrospect, iCloud’s public debut wasn’t without its issues and hiccups, but it was relatively smooth in the following days and Apple acted promptly to restore interrupted services for its users. Looking back, it’s just weird how many times iCloud Mail has been down, and continues to be unstable, whereas iCloud sync (for apps and data) has been fairly responsive and, at least on my side, always up. This says a lot about priorities, I guess.

In 107 days since iCloud went live, and 235 since Apple’s announcement at WWDC ‘11, it appears the majority of third-party developers are still considering whether or not iCloud is something worth investing their time – and customers’ money – or not. Those who have successfully implemented iCloud have done so in ways that require minimal user interaction, most of the times enabling sync capabilities through a single setting switch. Others have tried more complex solutions, often having to come up with separate tools to enable iCloud. Especially on the Mac, the fact that only apps sold through the Mac App Store can be directly integrated with iCloud isn’t helping developers who are still selling apps both on Apple’s App Store and their own website. Overall, there seems to be a shared trend among developers choosing to wait for Apple to clarify specific aspects of iCloud sync, improve the platform and fix some bugs that may prevent certain applications from being iCloud-enabled without requiring a major restructuring of the codebase on their end. Turning an iOS or Mac app into an iCloud-enabled app hasn’t turned out to be the 1-click process many, including me, wrongfully assumed when iCloud was previewed at WWDC last year.

Every app has its own way of storing local documents and user data. Some apps prefer keeping the original source of a document intact, say a .txt file, whilst others may apply their own file format to store documents and data internally in a proprietary database or multiple files, such as Evernote’s take on XML. There are pros and cons: keeping a universal file format such as plain text gets you more benefits in data portability; writing your own database structure allows you, as a developer, to do things exactly the way you want. What does this mean for iCloud?

Without getting too technical (also because my knowledge on the subject can only get you so far before I suggest you go read the developer documentation), the developers I’ve talked to explained that in the way iCloud syncs file, there may be some incompatibilities with apps that are based on complex databases and libraries. Apps that simply want to sync .txt files across multiple devices might be easier to port to iCloud, but then again there are always some aspects to consider such as conflicts, renaming a file, or getting a timestamp for the modification date when multiple devices are accessing iCloud. That’s not to say implementing iCloud is technically impossible for apps that are based on libraries, and not easily exportable files: below, I’ve collected some examples of apps that do just that, and quite cleverly too. However, getting to enable iCloud and make it reliable enough so that all kinds of apps can work with it without frustrating the user (who, in theory, never has access to the inner workings of iCloud) while at the same time providing the functionalities he or she expects. Read more