With iCloud, everything happens in the background.
Devices running iOS 5 automatically back up when they're plugged in and not in use. Photos taken throughout the day are uploaded to your Photo Stream, where they are synced to your other devices, kept permanently on your computer, and stored for 30 days on Apple's Photo Stream servers. Bookmarks, contacts, the last page you read in your current book -- every bit and byte of data -- is also automatically backed up and shared with your other devices.
MobileMe and Google users may not be initially impressed. While MobileMe subscribers have been able to sync much of their data to and from their computers and phones for years, they also had to pay $99 a year for the service. Google users pay nothing, but have comparatively limited data syncing abilities.
iCloud, which will replace MobileMe, is also free (for the first five gigabytes, not including photos or iTunes purchases). And, working in concert with iOS 5, it makes it possible for iPhone, iPad and iPod touch owners to truly cut the cord.
Why iCloud matters
The arrival of iOS 5 and iCloud means that any of those devices could conceivably serve as your only computer. Out of the box, a setup assistant similar to the one used in Mac OS X 10.7 "Lion" appears on the screen, walking a user through basic questions such as the iCloud user name and password, and whether Location Services should be enabled.
You can set up the new device using an iCloud backup right from the initial setup assistant. And instead of just copying over your contacts, calendars and email, iCloud restores include every bit of data stored on your old device.
Why is this important? User experience and reliability.
You know how every IT guy says you should have backups of your computer? Just like Time Machine on the Mac, Apple's backup service will provide a permanent safety net. But iCloud goes beyond Time Machine because it's completely automatic. Whenever your device is plugged in and connected to wireless -- like when you plug your phone in to charge it up overnight -- a backup will automatically begin.
This opens up the iPhone and iPad to would-be buyers who couldn't, or wouldn't, purchase because you also needed a computer running iTunes to sync it with. Not everyone can afford several computing devices.
There's also the audience that feels computing is too hard. The iPhone has always been about ease of use, which made Apple's methods of getting data such as documents and photos on and off through iTunes surprisingly convoluted. By making photos and document sharing automatic, Apple is effectively making access to the file system obsolete. (Techies might not like what Apple has done for the opposite reason: They want access to the file system and don't want to see it go away.)
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