Apple pulled a sneak attack seemingly out of nowhere on Thursday morning, introducing the next version of the Mac operating system, OS X Mountain Lion, with no keynote address and by presenting it to a select group of journalists even before developers could get their hands on it. So what do we know about it so far?

Apple reached into its magic hat and pulled out not a rabbit, but rather a new cat this week: A mountain lion, to be exact, which will be unleashed this summer in the form of OS X Mountain Lion, essentially Mac OS X 10.8 -- although Apple isn’t officially calling it that anymore. Curious about what’s new? Read on to find out.

The Name’s X… OS X

Apple is showing a renewed commitment to the Mac with OS X Mountain Lion, which marks the beginning of annual major upgrades for the desktop in the same way the company has been doing for iOS from the beginning. But get ready for a shocker, because the operating system is no longer called “Mac OS X” but simply “OS X,” which developers discovered after installing the beta on Thursday and pulling up the About This Mac window.

While such a move would normally launch a thousand conspiracy theories about Apple’s future intentions for the Mac platform, the company has already made it clear that the Mac is here to stay -- they’re simply choosing to simplify the naming, although OS X and iOS will likely continue to consolidate feature sets over time.

Goodbye, Software Update

Or rather, hello to Software Update inside the Mac App Store! Developers poking around with OS X Mountain Lion have discovered that Apple is working hard to remove any potential confusion from the next major update, which OS X Lion certainly introduced by having certain updates available in the traditional Software Update mechanism and others only available in the Mac App Store. The one and only place will now be the Mac App Store, and users will be notified of updates with badges on the app icon when it’s placed in the Dock (the default method).

Gatekeeper Isn’t as Menacing as It Sounds

There’s no doubt Apple would prefer everyone to download Mac apps from the Mac App Store, although at the same time, they acknowledge that’s impossible for many software packages. To prevent users from installing potentially malicious software downloaded outside of the Mac App Store, OS X Mountain Lion introduces Gatekeeper, which uses a new “identified developer” program. Such developers register their software with Apple and receive a personalized certificate used to sign their apps; by default, Gatekeeper will allow apps from both the Mac App Store and these identified developers, and users will be responsible for allowing the installation of everything else.

Unlike the App Store itself, Apple doesn’t act as a true gatekeeper -- any developer can request the necessary certificate without showing Apple their code. Should an app be found to have gone rogue for some reason, Apple will simply blacklist that developer’s certificate, and Gatekeeper will prevent the app from opening on the user’s system, presumably unless the user has the software set to allow all apps.

iCloud Gets More Useful

Don’t get us wrong: We love iCloud. However, it happens to be far more useful on our iOS devices than it does on our Macs. But that will start to change with OS X Mountain Lion, with a more integrated easy setup -- sign in once and you’ll get iCloud in Mail, Contacts, Calendar, Safari, the Mac App Store and FaceTime.

Even more intriguing, OS X Mountain Lion will now offer two methods for accessing documents: The traditional Open and Save dialog boxes, but for apps that support Documents in the Cloud, you’ll also get a new iCloud view, which can be organized using iOS-style folders, plus a less unique On My Mac button for opening any file on your hard drive.

iOS Invades OS X

OS X Mountain Lion continues the “back to the Mac” theme started with OS X Lion, carrying over familiar apps like Reminders, Notes and Game Center as well as the new Notifications preference pane, which will control an iOS-style Notifications Center. That last item will probably sound familiar to longtime users of Growl, but judging from early reports by developers, Apple’s implementation of the concept is far more seamless and user-friendly.

Three other apps are also getting rebranded with OS X Mountain Lion: You’ve probably already heard that iChat is gone, replaced by Messages, which is already available as a beta download for OS X 10.7.3 users from Apple’s website. iCal and Address Book are also getting the boot, at least in name only -- iCal will now be simply known as Calendar, while Address Book becomes Contacts, in keeping with their iOS equivalents.

Can I Share with You?

Apple is also bringing iOS 5’s sharing functionality over to OS X Mountain Lion with Share Sheets, which are best described as something similar to the sharing capabilities of Google’s Android. Click on a Share icon and a Share Sheet will pop up, featuring a variety of services that users can choose to share through -- Add to Reading List, Add Bookmark, Email, Message and yes, Twitter, which is now baked right into the desktop operating system as well as iOS, as are other Apple-blessed partners like Flickr and Vimeo.

Several More Things…

OS X Mountain Lion will also introduce some smaller but equally significant changes. AirPlay mirroring is likely to be huge with road warriors who prefer to cart a MacBook Air around instead of an iPad 2, allowing a 720p video stream to be thrown onto any HDTV connected to an Apple TV over Wi-Fi. We can also see this feature in use for extending a home theatre setup, say for watching Hulu content that’s not available from Hulu Plus, for example.

Safari isn’t being ignored with OS X Mountain Lion, either -- the browser finally gets a unified toolbar capable of both URL entry and search in a single place, with a much larger and more prominent Reader button and additional emphasis on the website domain you’re visiting, which appears bolder than the rest of the address (presumably to help thwart phising schemes).

Last but not least, OS X Mountain Lion will be big in China, where Apple has beefed up support for writing in Chinese, with an improved dictionary and text entry. The leading Chinese search provider, Baidu, is now built in to Safari, and Mail, Contacts and Calendar work with popular Chinese services such as QQ, 163 and 126.

You Might Need a New Mac

Cult of Mac is reporting that Apple “has abandoned support for Intel’s GMA 950 and x3100 chipsets,” which means the move from OS X Lion to OS X Mountain Lion may come at a steep price. While Cupertino is listing a minimum requirement of an Intel Core 2 Duo processor, the graphics chip requirement will effectively negate these Macs from running OS X Mountain Lion:

• Any Intel Core 2 Duo MacBook from late 2007 – late 2008 (Model Numbers: MB061*/B, MB062*/B, MB063*/B, MB402*/A MB403*/A MB404*/A, MB402*/B)

• The Mid-2007 Mac mini (Model Numbers: MB138*/A, MB139*/A)

• Late 2006 polycarbonate iMac (Model Number: MA710xx/A)

• The original early 2008 MacBook Air (Model Number: MB003LL/A)

Good thing it’s a brand new year, since there should be a slew of brand-new Macs marching out in the months to come before OS X Mountain Lion slinks down the mountainside and uses your aging Mac as its prey.

Great! When (and How) Can I Get It?

Patience, young grasshopper… good things come to those who wait, as the saying goes. Apple isn’t saying exactly how much OS X Mountain Lion will cost, but has confirmed that it will be a paid upgrade available exclusively from the Mac App Store -- no more USB thumb drives, as the company grudgingly did with OS X Lion last year.

There’s also no word on a release date, other than “late summer,” which could presumably be anytime in August or even September, if you’re one of those “glass is half empty” types. Developers are already poking around inside a beta release released on Thursday, and there will surely be more of those yet to come in the months ahead.

As always, stay tuned to MacLife.com to find out the latest on OS X Mountain Lion, and don’t forget to give the new Messages app a spin by downloading the beta from Apple’s website now.

Follow this article’s author, J.R. Bookwalter on Twitter

(Moutain lion image courtesy of Cult of Mac)