Earlier today Microsoft revealed that they were going to be bringing their popular digital assistant Cortana to Android and iPhone devices later this year.
Those apps will bring most of Cortana's capabilities to these platforms however, they will lack deep integration at the OS level.
"Some features require access to the system that aren’t currently possible with iOS or Android, so things like toggling settings or opening apps won’t initially be available in the Cortana companions for those platforms. Similarly, the ability to invoke Cortana hands-free by saying “Hey Cortana” requires special integration with the device’s microphone, so that feature will be limited to Windows Phones and PCs."
So Windows Phone's Cortana integration remains unique but is this just a natural progression of Microsoft bringing their services to other platforms or should they have kept Cortana as a Windows exclusive?