Sometimes you’re so engrossed in your work that when you end up missing crucial messages. Your phone is somewhere in your bag or lighting up soundlessly in the corner of your desk, and you don't realise it until it's too late. With Continuity, you can access your messages from whichever iThing you're on.
Also works to fool your boss into thinking you're working hard when you're actually having a conversation about tonight's plans.
How to activate
Go to Settings then Messages to make sure Text Message Forwarding is switched on. Select your iThing of choice and you’ll be prompted to enter a code that shows up on that iThing. After that, all systems are go and you can look forward to sending and receiving messages discretely on your Mac.
You can even message Android and Windows Phone users too from your OS X Yosemite ready Mac. True story.