How to monetize the user is still wide open, but Apple will be covering the storage and server tab. (With money added from heavy users. Casual users needn't pay.)
The dark side of this is that there doesn't appear to be a way for a browser or non-Apple product to interact with the stored data. So you trade free backend servers for writing software only for Apple customers and even then not when they sit down at a borrowed machine.
It's not an open cloud. I wasn't aware there was a strict definition.
What APIs do the iCloud.com web-apps use, then? ("Non-public ones" is the likely answer.)
So I'm hopeful that CloudKit will address these issues. Versioned schemas are great for updates but hard to get working initially. I'm sure iCloud has a lot of good ideas like that, but up till now they were simply too esoteric to get a handle on, and I think the general consensus was to avoid iCloud until it was ready for primetime.
A private and secure platform results in more adoption.