Consider, for example, a comparison between Windows Search and Spotlight.
As of OS X Yosemite, these two features will do many of the same things.
The Notification Center, Spotlight, Safari, Email and Calendar all in some way integrate with or borrow ideas from Apple’s mobile devices, making the desktop stronger in the process.
Unlike Microsoft, however, Apple only borrows ideas that work.
Yet, these features are accessed in drastically different ways.
Many desktop owners (and some laptop users, too) have protested against the disappearance of the Start Menu, and the need to enter the Metro interface to perform some tasks.
While these complaints haven’t fallen on deaf ears, the subsequent updates to Windows 8 have restored features at a lazy pace.
You can’t use it to run apps, but you can use it to store data, exchange data, and communicate with others.
The fact that Apple controls i Cloud, OS X and i OS provides a level of integration no other operating system can match, and allows all three platforms to work together as if they really were a single OS.