One last point of interest before we leave iMessage, which had been nagging at me ever since I heard that iMessage would work on Wi-Fi only iPads and iPhone Touches: what happens if you tried to send an iMessage from your iPad to someone who doesn't have iOS 5? I decided to try to send a text to my wife, who hasn't let me upgrade her phone's OS yet (she says she needs it to "make calls" or whatever). The iMessage app lets me select her contact information, but then immediately let me know that her phone number wasn't available -- a fairly graceful way to handle it.
Watch that data sync!
If for some reason you really want to see iCloud in action in real time, an easy way to do it is by playing with your Contacts app. To start, gather up every iCloud-enabled platform you can muster. The picture below shows my iPad, iPhone, personal laptop (with the Address Book application open) and work laptop (with a browser window pointing to the Contacts app on the iCloud Website). Yes, it's a bit much! I'm a professional tech journalist, but hoarding electronics is a serious problem.
You can now add, erase, or edit a contact on any one of these devices and watch the changes percolate out through the cloud and then back to your other gadgets. If you want to speed the process up on the iCloud Website, there's a "Refresh" command you can invoke:
There's no equivalent to this on the iOS or OS X apps. But honestly, in most cases it didn't take more than a few seconds for the changes to show up everywhere. The laggard in this regard was the iPhone, which sometimes wouldn't update for up to a minute; but in general, the process worked seamlessly, and was kind of fun to watch (for certain very dorky definitions of "fun"). The key takeaway from the experience was to reaffirm that the definitive version of my contact data was now not resident on any specific device. Each gadget offered a slightly time-delayed front end to the real data, which on Apple's servers, and I can edit that data from whichever of those front ends that happen to be convenient to me. And yet, if the iCloud servers exploded tomorrow, I wouldn't have lost my data, as there'd be local versions everywhere. In some ways it's the best of both worlds.