Google's Nexus line of phones and tablets has always had one draw for buyers -- the use of stock Android. Nexus products have always debuted with what's come to be known as Android in its purest form, without modifications by an OEM or a carrier. That was assumed to continue with Google's latest member of the Nexus line, theIt turns out that's not the case as several features of "stock" KitKat on the Nexus 5 are exclusive to that phone.
Using a pure form of Android on the Nexus products has been a good draw for those wanting to skip any augmentations from companies outside Google who customize their versions of Android. Nexus buyers could be sure that what they were getting on their Nexus phone or tablet was stock Android. This meant it was a pure Google phone, outside of the hardware.
That's still sort of the case with the latest phone, the Nexus 5. The Android used on the Nexus 5 is pure Google, but according to J. R. Raphael of Computerworld, Google has confirmed that a few features on the Nexus 5 will not be part of KitKat distributed to other partners. These features include the home screen integration of Google Now and the ability to initiate a Google search by speaking "okay, Google" while on the home screen.
This is significant as the version of Android previously used on Nexus products has been the raw version that OEMs get for modification. With exclusive features on the Nexus 5, Google is behaving like its partners and customizing Android for its own products. It may give reasonable excuses for such customization, but the fact is now stock Android is fragmented, and by Google.
This may turn out to be a minor event, but it's such a big change from the status quo that it's worth noting. It means there is no such thing as stock Android that is available to customers by Google. While fragmentation has long been a complaint about Google, that's never been the case with devices by Google. Until now.