Sneaky bunch at Microsoft!
They created a beautiful new design language for Windows Mobile, that's since made its way all around the Windows brand. Since purchasing Skype there has been signs of the Skype brand slowly and subtly adopting elements of the MSoft brand.
When it came time for Skype to redesign their iOS app those clever pixel wranglers threw away any references to the Apple iOS language. They've taken the Windows Design language, smashed it with the Skype brand and put it in your iPhone. Possibly one of the trickiest UI/Brand design challenges imaginable and the team at Skype have done a lovely job of it. The translation of the Windows UI is subtle enough to make it feel distinctly Windows, but the details in the surrounding elements (moving clouds, wobbling menus etc) keep it firmly in the Skype personality.
Along with the new UI comes this nice little clip that plays in the app when it first loads.
The Skype Design teams showing huge talent in bringing together facets of the UX.