For one, you'll be able to start answering phone calls and sending and receiving text messages from your Mac.
In fact, the reason Yosemite is so significant is that it really begins to bring the Mac and the iPhone together in a meaningful way. Yosemite, which will be made available for free in the Mac App Store, includes a total visual overhaul of OS X that introduces a simple and colorful style, much like what's found on iOS. Apple is releasing OS X Yosemite today, launching what is arguably the most significant update to the Mac's operating system in years.
