Apple's Worldwide Developers Conference kicked off on Monday with the much-anticipated keynote introduced by CEO Tim Cook. But one of the centerpieces of the keynote was demonstrated by Craig Federighi, SVP of Software Engineering for Apple: the new OS X "Yosemite," the most mobile-seamless OS for Mac yet.

After a comic bit about Apple's "crack team" of marketing people looking for a new California-location based name for the new OS X that would follow up OS 10.9's "Mavericks" -- named after a surfing spot in California -- which included a punchline offering of OS X "Weed" named after the northern California region (Apple's 2014 keynote was distinctly more lighthearted than previous years), the serious discussion about the next generation of Mac OS X began.

Meet OS X Yosemite

Named after Yosemite national park, the new version of OS X includes several design elements from iOS 7. Clear typography, clutter-free default organization, flat graphics for application icons, and translucent windows all comprise the new appearance of the more iOS-friendly Mac operating system.

But there would be more announcements to come about changes under the hood, for both OS X Yosemite and iOS 8, that will tie the two operating systems together like never before.

New, Powerful Native Apps and Welcome Updates

First, here are some big changes to OS X that will likely make your everyday experience much more fluid and easy.

Spotlight: Sherlock Resurrected

One of the centerpieces of the new OS X Yosemite is something perhaps a little unexpected, but entirely welcome, after the fact. Apple updated its Spotlight App to become much more useful than the little clunky magnifying glass in the corner most Mac users have come to ignore.

The new Spotlight literally takes center stage on Apple's OS X, appearing in the middle of the screen whenever you need to search for anything. And they mean anything. Taking a page from Google's and Microsoft's enhanced, web-integrated search bars, Apple's Spotlight will not only bring up files, mail, and locally stored media, but also apps for instant launch, contact information, and suggestions from the web, including mini Wikipedia preview entries (if you search for a famous figure, for example).

To be fair, Apple had tried web search integration before in early versions of OS X and Sherlock, but of course the web and internet connectivity has come a long way since then, and it makes sense to resurrect that feature now.

"Today" View in Notifications Center

Another, more recently introduced (in Mavericks), feature that nevertheless felt a little underpowered and less than necessary was the Notifications Center, also located in the overlooked top-right corner of OS X. A new view option called "Today" view may change all of that. "Today" gives you a quick look at every calendar item, reminder, stocks, weather, and other custom widgets -- it sounds a lot more attractive and useful than the current Notifications Center, which is basically a lackluster compilation of your mail, social media, and reminders.

Enhancements to Safari and Mail

Apple updated its system web browser, Safari, to include a more powerful Spotlight-powered web search, more enhancements under the hood, a better way to use tabs, and a cleaner interface. For example, the browser still allows you to have a favorites bar, but because your top favorite sites appear below in a grid as soon as you click on the URL/Search bar, Federighi bets you won't even need to clutter up the top of your browser with a favorites list.

Browsing tabs also got a redesign to be more useful and accessible, without adding to screen clutter. Now, without changing tabs, you can scroll through all open tabs to clearly see what's open and what can be closed. There's an all tabs view that collects tabs in common groups and displays them all as a clearly defined grid, as well. One more feature for the power tab browser (especially the on-the-go variety): according to Apple, the company has reengineered Safari to allow for maximum open tabs with maximum power savings -- far more than the two other top browsers, Firefox and Chrome. Apple pointed out several other enhancements to power saving and speed of browsing with the new Safari as well, like the fastest JavaScript performance of any major web browser, according to Federighi.

The Mail app got an update as well. On OS X Yosemite, Mail will be faster and more reliable, claims Apple, and with a couple of cool new features. One is Annotations, which allows users to hand-draw graphics that save into documents like PDFs, picture, and other attached media. Obviously, one of the top advantages of this feature is the ability to sign documents and return them without involving that classic example of analogue/digital clunkiness: the print-sign-scan routine.

It also gives you an easy way to mark up documents and have fun with photos in what looked like an almost transparently "Snapchat-for-email" demonstration on stage at WWDC Monday.

OS X and iOS: Not Twins, But No Longer Distant Cousins

As mentioned at the top, OS X and iOS are now closer than ever. But it's not just in looks (though look at how much this new UI resembles iOS 7 — especially the Dock!).

OS X Yosemite will allow the Messages desktop app to send SMS texts through your iPhone to recipients. You can record short audio clips to send as well. But that's not even the half of it.

With a Mac running OS X Yosemite, and a nearby iPhone running iOS 8, Apple users will be able to basically hook up their iPhone for network data with one single click of an option called "Instant Hotspot" (without having to set up a hotspot on your iPhone, choose passwords, etc.).

Even better, with those two devices and updated OS's, you'll be able to send and receive phone calls from your computer. There's even a caller ID that pops up on your OS X desktop when a call comes in.

Finally, there's a suite of applications under what Apple calls "Continuity" that tie together your iPhone and Mac computer in new ways. iCloud Drive, for example, puts your iCloud account directly in your finder for easy file storage, organization, and search -- which also instantly updates your iCloud account between iPhone, iPad and Mac.

Then there's "HandOff" which lets you instantly take a task you're working on in the iPhone (like writing an email) and with a gesture, send it instantly to your Mac to continue working - and vice versa, including with iPad. Apple makes HandOff look like AirDrop — except it's instant, mid-progress, and includes more types of data than just media files. Also, AirDrop now works between Mac and iOS devices, thus making it useful for the first time.

With these Continuity Apps, along with the enhanced Instant Hotspot and call and text forwarding from the iPhone, OS X Yosemite looks like the closest thing, so far, to a hybrid OS X/iOS system, while still retaining the distinctiveness of both mobile and desktop operating systems. But it remains to be seen just how seamless Mac and mobile can be together, and how many kinks in the system show up when Yosemite is not carefully being unveiled to the world.

Luckily, you'll have an opportunity to see for yourself, as well as to help Apple work those kinks out. OS X Yosemite is officially releasing in the Fall, along with iOS 8 and (presumably) some new Apple devices. But as early as this summer, Apple is opening the first-ever early open public beta test for those interested. You can sign up here if you are.

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