A tweet from a source supposedly close to Microsoft suggests that Terry Myerson, Redmond's top OS man on the totem pole, has decided to merge Windows Phone and Windows RT; this is not going to happen with a snap of the fingers, and will require 3 GDR updates a year over two years. We've already told you that Microsoft is merging the Windows Phone Store and the Windows Store, which is one of the first moves toward merging the two platforms...
Source: http://www.phonearena.com/news/Windows-Phone-and-Windows-RT-to-merge_id48016
Source: http://www.phonearena.com/news/Windows-Phone-and-Windows-RT-to-merge_id48016