--------------------------------------------------------------------------------------------------------------------------------------
Reason 1. One OS for all Android smartphones. Google has an ambitious goal — to bring all Android devices to one mobile platform by 2014: ‘We have one version of the OS that'll run across all Android smartphones in 2014’, said Sundar Pichai. That sounds like the notorious problem of Android fragmentation is coming to an end. Instead of putting efforts into support of outdated Android versions, developers can finally concentrate on making good apps for just one version.
--------------------------------------------------------------------------------------------------------------------------------------
Would love to just copy the whole article but maybe it is better you go and read the rest here:
http://blog.azoft.com/android-kitkat-for-android-developers/