An email sent from Apple to a MobileMe member reveals some details about Apple's upcoming storage allocation in iCloud. When users sign up for a free iCloud account, they will receive 5 GB of cloud storage. However, when users near their 5 GB limit, they'll receive an email from Apple like the one this MobileMe member received today, as MacRumors reported. The email reveals what happens if you hit your 5 GB limit.
If you max out your data storage, your iOS devices will no longer back up or save new data to iCloud, and any emails sent to your me.com email address will bounce back to the sender. The good news is that media or apps that you purchased through iTunes don't count against your 5 GB iCloud allotment.
Still, if you're going to be saving many large files on iCloud, you're probably going to need more than the 5 GB of free storage eventually. The email from Apple states that iCloud users can buy more storage right from their iOS devices or on a Mac or PC; it doesn't, however, state any pricing or in what increments users can buy additional storage.
iCloud is expected to fully roll out in the fall with the release of iOS 5, but users with an iTunes account can test out some of its services now by redownloading apps they've already purchased.