Apple released a developer preview for OS X 10.8 Mountain Lion today, and it finally makes the Mac an equal iCloud citizen, alongside the iPhone and iPad. Previously, iCloud could be enabled as a sync tool for OS X, and a way to re-download iTunes content, but versions of apps like iWork for Mac weren't updated to take advantage of Documents in the cloud.
Now Documents in the Cloud is a core part of OS X, a secondary, simplified file system that aims to make keeping copies of your important files as easy on the Mac as it is on iOS.
"It just works. In more ways than ever. In OS X Mountain Lion, sign in once with your Apple ID and iCloud is automatically set up across your Mac.1 That means right away iCloud keeps your mail, calendars, contacts, documents, and more up to date on every device you use. So when you add, delete, or edit something on your Mac, it happens on your iPad, iPhone, and iPod touch. And vice versa."
iCloud was previously described by Tim Cook as more than just a service, but Apple's strategy for the next decade. That seems to be very true, judging how many of today's preview announcements at least have hooks in iCloud, if not being full integrated already.
Since they've got hardware more or less on lock, now Apple is smartly following up by competing in the services realm. Of course, there are product-side implications, too. All of these changes inch Macs and iPads closer together, and in so doing, setting the stage for the day when Apple tablets are more like really small computers rather than really big iPhones.
More: Mountain Lion on Apple.com.