I have been exploring iOS 5 beta 1 for a while now posting many new features and tutorials to make the maximum use of iOS 5. iCloud is definitely an amazing feature inclusion in iOS 5. You can now sync your contacts to iCloud, Sync apps via iCloud, Creating a new iCloud ID on iOS 5 and so on.
While setting up your iOS 5 device for the first time, it allows you to create a @me.com account, that will be associated with your current Apple ID.
But iCloud IDs come with a restriction now. You can only create 3 free iCloud IDs per device and not more than that. I got a message saying “This device is no longer eligible for creating a free MobileMe account.”, when trying to create the fourth iCloud ID. Guess this is a good move by Apple.
How will Apple find my iDevice’s account limit?
Upon exploring more on this limitation and testing it out on other devices, Apple validates this through the UDID and I don’t think there is any way to create more than 3 MobileMe IDs on the iDevice.