It works in the other direction, too. If you start an email on the iPhone and return to your Mac, an email app icon will display on the left hand side of the Dock. Clicking on that icon will open up the email you were composing on the iPhone right where you left off. And that's just one example; Handoff works with many of Yosemite's built-in apps, and the technology is open to developers so they can incorporate these features into their apps.
AirDrop lets iOS and Mac users share documents, photos, videos and other data wirelessly and securely. The difference with AirDrop in Yosemite and iOS 8 is that (finally) Macs can wirelessly transfer files to iOS devices and vice versa.
Automatic Hotspot is a feature I initially underestimated. This is a zero-configuration personal hotspot, allowing your Mac to access the Internet using a cellular-connected iPhone or iPad. With this feature, any cell-enabled iOS 8 device logged in with your iCloud information can be easily set up to be used as a hotspot. iOS 8 devices just show up under the Mac's Wi-Fi list — a single click grants you access to the internet.
This feature can really come in handy. My neighborhood suffered a power outage over the summer. On a whim, I clicked on the Wi-Fi icon in the Mac's menu and noticed that my iPad and iPhone were listed. One click later, my MacBook Pro was back online, no muss, no fuss. That's impressive.
Another great feature is the ability to make and receive phone calls from the Mac or another iOS device. For example, if your iPhone is being charged on the other side of the house and you receive a phone call, your Mac and other iOS devices now display the Caller ID information, and you can pick up the call on any device. It works the other way, too — if you dial a number from your Mac or iPad, the devices will use the FaceTime app to route the call through the iPhone, including numbers from contacts or webpages.
Finally, SMS support lets your Mac or iPad send SMS and MMS messages right from their respective apps. (Previously, only iMessages between Apple devices were possible in the existing app.) This feature is due in October.
As you can see, the features in Continuity extend the usefulness of Apple products by allowing new kinds of interaction between devices. Unfortunately, unless you signed up for the public beta program, you'll have to wait until Yosemite is released in October. Trust me: These features are worth the wait.
Speaking of waiting: Many iPhone fans have wondered whether Apple engineers would ever allow the use of third-party software to extend functionality and, with iOS 8, that wait is (mostly, kind of) over. iOS 8 has some features that will give developers the ability to extend the operating system without compromising security through Extensions.
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