Google is announcing some new additions to its Drive SDK that borrow a page out of the iCloud playbook, helping developers use Drive as a dependable place to store application data by locking the user out. The first addition, called app data folders, can be used to store files that you would want to hide from the user — things like configuration files or app state data. The user never sees the contents of the folders, only how much data apps are using, and he or she can clear that out to free up space from a Manage Apps dialog.

The second addition is custom properties, which let developers use key-value pairs to store simple data. These keys and values can either be kept private or made publicly visible to other apps. As an example, Google suggests using custom properties to keep track of a document's status as it goes through a review process — you might want to make the word count or last revised date of that document directly available to other apps on the user's device, for instance. Right now, iCloud doesn't provide an equivalent — apps can store key-value pairs, but there’s no way to mark that information public so that it’s visible to other apps.

It’s interesting to see that Google is giving Drive more iCloud-like features, rather than simply keep it a Dropbox-like repository for documents. The company is also stopping short of offering the kind of database syncing that has proved so problematic for Apple, which is interesting to see from Google, since one of the company's great strengths is the robustness of its cloud services. Lastly, the Drive SDK differs from iCloud in another important way — it's cross-platform, and can be used by Android and iOS apps alike.