July 25, 2012 at 5:09 PM ET
Mountain Lion — the latest version of Apple's OS X — is now available in the Mac App Store for $19.99. And it's definitely a worthwhile operating system upgrade.
Here's why.

Hello, Mac! Hello, mobile!
Mountain Lion is basically a way for Apple to bring its mobile and desktop operating systems closer together. Now your iPad, iPhone and Mac will get along better than ever. Your documents, notes, calendars, messages, reminders, Safari tabs and more will sync across devices smoothly thanks to Mountain Lion. (And things will get even cozier when iOS 6 arrives in the fall, of course).

Everything in its place ... and a place for everything
A brand new Notification Center will help keep you organized in Mountain Lion. It's a pane that slides out from the right-hand side of your screen, displaying a selection of alerts and banners which allow you to track activities easily.
Alerts (meeting notices, for instance) are little pop-ups which will linger in the top-right corner of your screen until you dismiss them while banners (announcing incoming emails, etc.) will disappear after five seconds.
If you want to see anything you've missed, just slide open the Notification Center with a two-fingered swipe and look at a list of up to 20 recent notifications per app. These can include activity from Calendar, Mail, Messages, FaceTime, Reminders, GameCenter, Twitter and many third-party apps. In the fall, there will be support for Facebook as well.

You can configure the type of notifications — alerts or banners — that'll appear for each app as well as associated sounds and the like in your settings. Everything can be tweaked on a per-app basis. And if things get too overwhelming, there's a little toggle that'll silence all pop-up notifications until the next day.
Safety first
Mountain Lion has a security feature called Gatekeeper intended to keep your computer safe from the dangers of the wild wild Web. Gatekeeper basically prevents you from inadvertently installing malicious software. The security feature checks every app to see if it came from the Mac App Store or a developer who has been issued a unique Developer ID by Apple. This way there's some assurance that the apps you're installing are coming from a known entity with a decent track record.

Sharing is caring
Mountain Lion encourages sharing more than any prior version of Apple's desktop operating system. There's even a "Share" button built into most Mountain Lion apps, allowing you to easily share links, photos, videos, and more using Mail, Messages, AirDrop, Twitter, Facebook, Vimeo or Flickr. (How an item can be shared depends on the file type and app, mind you.)
Thanks to the way sharing is baked right into Mountain Lion, you'll rarely ever have to leave an app in order to share an item. It's one less step or distraction to deal with.

Be more social
Considering how much emphasis there is on sharing and communication within Mountain Lion, it should be no surprise that there is also built-in support for the two most predominant social networking services. The Facebook integration won't be available until the fall — when it will arrive in the form of a software update — but you can already enjoy some great Twitter-related features in Mountain Lion.
You only have to sign into the services once, within the "Mail, Contacts & Calendar"section of your settings, and you'll be all set to go. You'll be able to tweet or post to Facebook using the Share menu found in many Mountain Lion apps as well — and even from a special box at the top of the Notification Center.
Your Facebook friends and Twitter contacts can be imported directly into your contacts as well, so you can always have up-to-date info on your pals. Birthdays listed on Facebook profiles can also be automatically added to your Calendar.
You'll also be able to get alerts or banner notifications for status updates from either social network.

Mirror, mirror on the ... TV?
Thanks to AirPlay mirroring, you can wirelessly send whatever's on your Mac to an HDTV, via the $99 Apple TV box. There's support for 1080p video (if you have the latest Apple TV) and content will be scaled to best fit your TV, so everything should look as good as possible. Of course, everything's encrypted, so you can feel secure when you beam things to your TV.
Not all Macs support the AirPlay mirroring, but Apple says that the following models are compatible:
If you are unsure of your model's age, call the Apple Store and ask them for help.
Nap time
Many of us leave our computers on, just snoozing through out the day. Power Nap is a feature which will help keep everything up to date when your computer is sleeping. It works silently — receiving email, syncing calendar invites, downloading software updates, keeping Find My Mac running, and more. Whenever you're ready to wake your computer up, you'll find that it's perfectly synced to your iOS and other OS X devices.
And don't worry about Power Nap draining your battery. It'll automatically shut itself off if your power level dips below 30 percent.

Surf's up!
Say what you will about Safari's past, in Mountain Lion it makes surfing the Web a pleasure.
There's one spot — dubbed the "smart search field" — in which you can enter searches as well as Web adresses. (You can pick your favorite search engine, of course.)

A quick pinching gesture will reveal a new tab view, which will allow you navigate between open (and live) tabs by swiping back and forth. This may not sound like much, but it is quite possibly one of our favorite little tweaks in Mountain Lion.
The big little things
There are a lot of features and changes within Mountain Lion which you won't even realize exist until you really need them for a task or stop to think about why something "just works." They're the big little things that make life simpler or more fun.
Will this kitten scratch?
As with any operating system update, it's not all sunshine and snuggles when it comes to Mountain Lion. Some folks will feel as if all the little changes don't add up to a decent upgrade; others will be disappointed that Mountain Lion isn't a perfect mirror of iOS for the desktop, and so on.
But let's be realistic: You're paying $19.99 for an operating system upgrade which contains over 200 new features. Yes, some of them are minor, but there is some strength in numbers. And besides: You'll have an excuse to make purr-fectly silly cat-themed puns after updating.

Getting your computer ready for Mountain Lion
Convinced that this is the update for you? Great! There are a few things you should do before rushing off and attempting to download Mountain Lion though:
Got all those little things checked off? Wonderful! Head over to the Mac App Store and grab Mountain Lion. Use it for a while and then come back here and tell us what you think about it.
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