Well, maybe some apps like Facebook, BBM, Flipboard or else 'gone' from Play Store after flashing AOSP KitKat.
It happen to me and I found this thread. It fixed my problem after step number 3, instead of 5 : )
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?